1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Mathew Kotowsky <kotowsky@sctp.org> 40 * Sridhar Samudrala <samudrala@us.ibm.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Dajiang Zhang <dajiang.zhang@nokia.com> 44 * Daisy Chang <daisyc@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * Ryan Layer <rmlayer@us.ibm.com> 47 * Kevin Gao <kevin.gao@intel.com> 48 * 49 * Any bugs reported given to us we will try to fix... any fixes shared will 50 * be incorporated into the next SCTP release. 51 */ 52 53 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 54 55 #include <linux/types.h> 56 #include <linux/kernel.h> 57 #include <linux/ip.h> 58 #include <linux/ipv6.h> 59 #include <linux/net.h> 60 #include <linux/inet.h> 61 #include <linux/slab.h> 62 #include <net/sock.h> 63 #include <net/inet_ecn.h> 64 #include <linux/skbuff.h> 65 #include <net/sctp/sctp.h> 66 #include <net/sctp/sm.h> 67 #include <net/sctp/structs.h> 68 69 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 70 const struct sctp_endpoint *ep, 71 const struct sctp_association *asoc, 72 struct sctp_chunk *chunk, 73 const void *payload, 74 size_t paylen); 75 static int sctp_eat_data(const struct sctp_association *asoc, 76 struct sctp_chunk *chunk, 77 sctp_cmd_seq_t *commands); 78 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 79 const struct sctp_association *asoc, 80 const struct sctp_chunk *chunk); 81 static void sctp_send_stale_cookie_err(struct net *net, 82 const struct sctp_endpoint *ep, 83 const struct sctp_association *asoc, 84 const struct sctp_chunk *chunk, 85 sctp_cmd_seq_t *commands, 86 struct sctp_chunk *err_chunk); 87 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 88 const struct sctp_endpoint *ep, 89 const struct sctp_association *asoc, 90 const sctp_subtype_t type, 91 void *arg, 92 sctp_cmd_seq_t *commands); 93 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const sctp_subtype_t type, 97 void *arg, 98 sctp_cmd_seq_t *commands); 99 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 100 const struct sctp_endpoint *ep, 101 const struct sctp_association *asoc, 102 const sctp_subtype_t type, 103 void *arg, 104 sctp_cmd_seq_t *commands); 105 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 106 107 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 108 sctp_cmd_seq_t *commands, 109 __be16 error, int sk_err, 110 const struct sctp_association *asoc, 111 struct sctp_transport *transport); 112 113 static sctp_disposition_t sctp_sf_abort_violation( 114 struct net *net, 115 const struct sctp_endpoint *ep, 116 const struct sctp_association *asoc, 117 void *arg, 118 sctp_cmd_seq_t *commands, 119 const __u8 *payload, 120 const size_t paylen); 121 122 static sctp_disposition_t sctp_sf_violation_chunklen( 123 struct net *net, 124 const struct sctp_endpoint *ep, 125 const struct sctp_association *asoc, 126 const sctp_subtype_t type, 127 void *arg, 128 sctp_cmd_seq_t *commands); 129 130 static sctp_disposition_t sctp_sf_violation_paramlen( 131 struct net *net, 132 const struct sctp_endpoint *ep, 133 const struct sctp_association *asoc, 134 const sctp_subtype_t type, 135 void *arg, void *ext, 136 sctp_cmd_seq_t *commands); 137 138 static sctp_disposition_t sctp_sf_violation_ctsn( 139 struct net *net, 140 const struct sctp_endpoint *ep, 141 const struct sctp_association *asoc, 142 const sctp_subtype_t type, 143 void *arg, 144 sctp_cmd_seq_t *commands); 145 146 static sctp_disposition_t sctp_sf_violation_chunk( 147 struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 void *arg, 152 sctp_cmd_seq_t *commands); 153 154 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const sctp_subtype_t type, 158 struct sctp_chunk *chunk); 159 160 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 161 const struct sctp_endpoint *ep, 162 const struct sctp_association *asoc, 163 const sctp_subtype_t type, 164 void *arg, 165 sctp_cmd_seq_t *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: 1 = Valid length 171 * 0 = Invalid length 172 * 173 */ 174 static inline int 175 sctp_chunk_length_valid(struct sctp_chunk *chunk, 176 __u16 required_length) 177 { 178 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 179 180 if (unlikely(chunk_length < required_length)) 181 return 0; 182 183 return 1; 184 } 185 186 /********************************************************** 187 * These are the state functions for handling chunk events. 188 **********************************************************/ 189 190 /* 191 * Process the final SHUTDOWN COMPLETE. 192 * 193 * Section: 4 (C) (diagram), 9.2 194 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 195 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 196 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 197 * should stop the T2-shutdown timer and remove all knowledge of the 198 * association (and thus the association enters the CLOSED state). 199 * 200 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 201 * C) Rules for packet carrying SHUTDOWN COMPLETE: 202 * ... 203 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 204 * if the Verification Tag field of the packet matches its own tag and 205 * the T bit is not set 206 * OR 207 * it is set to its peer's tag and the T bit is set in the Chunk 208 * Flags. 209 * Otherwise, the receiver MUST silently discard the packet 210 * and take no further action. An endpoint MUST ignore the 211 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 212 * 213 * Inputs 214 * (endpoint, asoc, chunk) 215 * 216 * Outputs 217 * (asoc, reply_msg, msg_up, timers, counters) 218 * 219 * The return value is the disposition of the chunk. 220 */ 221 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 222 const struct sctp_endpoint *ep, 223 const struct sctp_association *asoc, 224 const sctp_subtype_t type, 225 void *arg, 226 sctp_cmd_seq_t *commands) 227 { 228 struct sctp_chunk *chunk = arg; 229 struct sctp_ulpevent *ev; 230 231 if (!sctp_vtag_verify_either(chunk, asoc)) 232 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 233 234 /* RFC 2960 6.10 Bundling 235 * 236 * An endpoint MUST NOT bundle INIT, INIT ACK or 237 * SHUTDOWN COMPLETE with any other chunks. 238 */ 239 if (!chunk->singleton) 240 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 241 242 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 243 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 244 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 245 commands); 246 247 /* RFC 2960 10.2 SCTP-to-ULP 248 * 249 * H) SHUTDOWN COMPLETE notification 250 * 251 * When SCTP completes the shutdown procedures (section 9.2) this 252 * notification is passed to the upper layer. 253 */ 254 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 255 0, 0, 0, NULL, GFP_ATOMIC); 256 if (ev) 257 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 258 SCTP_ULPEVENT(ev)); 259 260 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 261 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 262 * not the chunk should be discarded. If the endpoint is in 263 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 264 * T2-shutdown timer and remove all knowledge of the 265 * association (and thus the association enters the CLOSED 266 * state). 267 */ 268 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 269 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 270 271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 272 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 273 274 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 275 SCTP_STATE(SCTP_STATE_CLOSED)); 276 277 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 278 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 279 280 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 281 282 return SCTP_DISPOSITION_DELETE_TCB; 283 } 284 285 /* 286 * Respond to a normal INIT chunk. 287 * We are the side that is being asked for an association. 288 * 289 * Section: 5.1 Normal Establishment of an Association, B 290 * B) "Z" shall respond immediately with an INIT ACK chunk. The 291 * destination IP address of the INIT ACK MUST be set to the source 292 * IP address of the INIT to which this INIT ACK is responding. In 293 * the response, besides filling in other parameters, "Z" must set the 294 * Verification Tag field to Tag_A, and also provide its own 295 * Verification Tag (Tag_Z) in the Initiate Tag field. 296 * 297 * Verification Tag: Must be 0. 298 * 299 * Inputs 300 * (endpoint, asoc, chunk) 301 * 302 * Outputs 303 * (asoc, reply_msg, msg_up, timers, counters) 304 * 305 * The return value is the disposition of the chunk. 306 */ 307 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 308 const struct sctp_endpoint *ep, 309 const struct sctp_association *asoc, 310 const sctp_subtype_t type, 311 void *arg, 312 sctp_cmd_seq_t *commands) 313 { 314 struct sctp_chunk *chunk = arg; 315 struct sctp_chunk *repl; 316 struct sctp_association *new_asoc; 317 struct sctp_chunk *err_chunk; 318 struct sctp_packet *packet; 319 sctp_unrecognized_param_t *unk_param; 320 int len; 321 322 /* 6.10 Bundling 323 * An endpoint MUST NOT bundle INIT, INIT ACK or 324 * SHUTDOWN COMPLETE with any other chunks. 325 * 326 * IG Section 2.11.2 327 * Furthermore, we require that the receiver of an INIT chunk MUST 328 * enforce these rules by silently discarding an arriving packet 329 * with an INIT chunk that is bundled with other chunks. 330 */ 331 if (!chunk->singleton) 332 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 333 334 /* If the packet is an OOTB packet which is temporarily on the 335 * control endpoint, respond with an ABORT. 336 */ 337 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 338 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 339 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 340 } 341 342 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 343 * Tag. 344 */ 345 if (chunk->sctp_hdr->vtag != 0) 346 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 347 348 /* Make sure that the INIT chunk has a valid length. 349 * Normally, this would cause an ABORT with a Protocol Violation 350 * error, but since we don't have an association, we'll 351 * just discard the packet. 352 */ 353 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 354 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 355 356 /* If the INIT is coming toward a closing socket, we'll send back 357 * and ABORT. Essentially, this catches the race of INIT being 358 * backloged to the socket at the same time as the user isses close(). 359 * Since the socket and all its associations are going away, we 360 * can treat this OOTB 361 */ 362 if (sctp_sstate(ep->base.sk, CLOSING)) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* Verify the INIT chunk before processing it. */ 366 err_chunk = NULL; 367 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 368 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 369 &err_chunk)) { 370 /* This chunk contains fatal error. It is to be discarded. 371 * Send an ABORT, with causes if there is any. 372 */ 373 if (err_chunk) { 374 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 375 (__u8 *)(err_chunk->chunk_hdr) + 376 sizeof(sctp_chunkhdr_t), 377 ntohs(err_chunk->chunk_hdr->length) - 378 sizeof(sctp_chunkhdr_t)); 379 380 sctp_chunk_free(err_chunk); 381 382 if (packet) { 383 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 384 SCTP_PACKET(packet)); 385 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 386 return SCTP_DISPOSITION_CONSUME; 387 } else { 388 return SCTP_DISPOSITION_NOMEM; 389 } 390 } else { 391 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 392 commands); 393 } 394 } 395 396 /* Grab the INIT header. */ 397 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 398 399 /* Tag the variable length parameters. */ 400 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 401 402 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 403 if (!new_asoc) 404 goto nomem; 405 406 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 407 sctp_scope(sctp_source(chunk)), 408 GFP_ATOMIC) < 0) 409 goto nomem_init; 410 411 /* The call, sctp_process_init(), can fail on memory allocation. */ 412 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 413 (sctp_init_chunk_t *)chunk->chunk_hdr, 414 GFP_ATOMIC)) 415 goto nomem_init; 416 417 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 418 419 /* If there are errors need to be reported for unknown parameters, 420 * make sure to reserve enough room in the INIT ACK for them. 421 */ 422 len = 0; 423 if (err_chunk) 424 len = ntohs(err_chunk->chunk_hdr->length) - 425 sizeof(sctp_chunkhdr_t); 426 427 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 428 if (!repl) 429 goto nomem_init; 430 431 /* If there are errors need to be reported for unknown parameters, 432 * include them in the outgoing INIT ACK as "Unrecognized parameter" 433 * parameter. 434 */ 435 if (err_chunk) { 436 /* Get the "Unrecognized parameter" parameter(s) out of the 437 * ERROR chunk generated by sctp_verify_init(). Since the 438 * error cause code for "unknown parameter" and the 439 * "Unrecognized parameter" type is the same, we can 440 * construct the parameters in INIT ACK by copying the 441 * ERROR causes over. 442 */ 443 unk_param = (sctp_unrecognized_param_t *) 444 ((__u8 *)(err_chunk->chunk_hdr) + 445 sizeof(sctp_chunkhdr_t)); 446 /* Replace the cause code with the "Unrecognized parameter" 447 * parameter type. 448 */ 449 sctp_addto_chunk(repl, len, unk_param); 450 sctp_chunk_free(err_chunk); 451 } 452 453 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 454 455 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 456 457 /* 458 * Note: After sending out INIT ACK with the State Cookie parameter, 459 * "Z" MUST NOT allocate any resources, nor keep any states for the 460 * new association. Otherwise, "Z" will be vulnerable to resource 461 * attacks. 462 */ 463 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 464 465 return SCTP_DISPOSITION_DELETE_TCB; 466 467 nomem_init: 468 sctp_association_free(new_asoc); 469 nomem: 470 if (err_chunk) 471 sctp_chunk_free(err_chunk); 472 return SCTP_DISPOSITION_NOMEM; 473 } 474 475 /* 476 * Respond to a normal INIT ACK chunk. 477 * We are the side that is initiating the association. 478 * 479 * Section: 5.1 Normal Establishment of an Association, C 480 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 481 * timer and leave COOKIE-WAIT state. "A" shall then send the State 482 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 483 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 484 * 485 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 486 * DATA chunks, but it MUST be the first chunk in the packet and 487 * until the COOKIE ACK is returned the sender MUST NOT send any 488 * other packets to the peer. 489 * 490 * Verification Tag: 3.3.3 491 * If the value of the Initiate Tag in a received INIT ACK chunk is 492 * found to be 0, the receiver MUST treat it as an error and close the 493 * association by transmitting an ABORT. 494 * 495 * Inputs 496 * (endpoint, asoc, chunk) 497 * 498 * Outputs 499 * (asoc, reply_msg, msg_up, timers, counters) 500 * 501 * The return value is the disposition of the chunk. 502 */ 503 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 504 const struct sctp_endpoint *ep, 505 const struct sctp_association *asoc, 506 const sctp_subtype_t type, 507 void *arg, 508 sctp_cmd_seq_t *commands) 509 { 510 struct sctp_chunk *chunk = arg; 511 sctp_init_chunk_t *initchunk; 512 struct sctp_chunk *err_chunk; 513 struct sctp_packet *packet; 514 515 if (!sctp_vtag_verify(chunk, asoc)) 516 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 517 518 /* 6.10 Bundling 519 * An endpoint MUST NOT bundle INIT, INIT ACK or 520 * SHUTDOWN COMPLETE with any other chunks. 521 */ 522 if (!chunk->singleton) 523 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 524 525 /* Make sure that the INIT-ACK chunk has a valid length */ 526 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 527 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 528 commands); 529 /* Grab the INIT header. */ 530 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 531 532 /* Verify the INIT chunk before processing it. */ 533 err_chunk = NULL; 534 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 535 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 536 &err_chunk)) { 537 538 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 539 540 /* This chunk contains fatal error. It is to be discarded. 541 * Send an ABORT, with causes. If there are no causes, 542 * then there wasn't enough memory. Just terminate 543 * the association. 544 */ 545 if (err_chunk) { 546 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 547 (__u8 *)(err_chunk->chunk_hdr) + 548 sizeof(sctp_chunkhdr_t), 549 ntohs(err_chunk->chunk_hdr->length) - 550 sizeof(sctp_chunkhdr_t)); 551 552 sctp_chunk_free(err_chunk); 553 554 if (packet) { 555 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 556 SCTP_PACKET(packet)); 557 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 558 error = SCTP_ERROR_INV_PARAM; 559 } 560 } 561 562 /* SCTP-AUTH, Section 6.3: 563 * It should be noted that if the receiver wants to tear 564 * down an association in an authenticated way only, the 565 * handling of malformed packets should not result in 566 * tearing down the association. 567 * 568 * This means that if we only want to abort associations 569 * in an authenticated way (i.e AUTH+ABORT), then we 570 * can't destroy this association just because the packet 571 * was malformed. 572 */ 573 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 574 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 575 576 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 577 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 578 asoc, chunk->transport); 579 } 580 581 /* Tag the variable length parameters. Note that we never 582 * convert the parameters in an INIT chunk. 583 */ 584 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 585 586 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 587 588 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 589 SCTP_PEER_INIT(initchunk)); 590 591 /* Reset init error count upon receipt of INIT-ACK. */ 592 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 593 594 /* 5.1 C) "A" shall stop the T1-init timer and leave 595 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 596 * timer, and enter the COOKIE-ECHOED state. 597 */ 598 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 599 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 600 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 601 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 602 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 603 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 604 605 /* SCTP-AUTH: genereate the assocition shared keys so that 606 * we can potentially signe the COOKIE-ECHO. 607 */ 608 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 609 610 /* 5.1 C) "A" shall then send the State Cookie received in the 611 * INIT ACK chunk in a COOKIE ECHO chunk, ... 612 */ 613 /* If there is any errors to report, send the ERROR chunk generated 614 * for unknown parameters as well. 615 */ 616 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 617 SCTP_CHUNK(err_chunk)); 618 619 return SCTP_DISPOSITION_CONSUME; 620 } 621 622 /* 623 * Respond to a normal COOKIE ECHO chunk. 624 * We are the side that is being asked for an association. 625 * 626 * Section: 5.1 Normal Establishment of an Association, D 627 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 628 * with a COOKIE ACK chunk after building a TCB and moving to 629 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 630 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 631 * chunk MUST be the first chunk in the packet. 632 * 633 * IMPLEMENTATION NOTE: An implementation may choose to send the 634 * Communication Up notification to the SCTP user upon reception 635 * of a valid COOKIE ECHO chunk. 636 * 637 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 638 * D) Rules for packet carrying a COOKIE ECHO 639 * 640 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 641 * Initial Tag received in the INIT ACK. 642 * 643 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 644 * 645 * Inputs 646 * (endpoint, asoc, chunk) 647 * 648 * Outputs 649 * (asoc, reply_msg, msg_up, timers, counters) 650 * 651 * The return value is the disposition of the chunk. 652 */ 653 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 654 const struct sctp_endpoint *ep, 655 const struct sctp_association *asoc, 656 const sctp_subtype_t type, void *arg, 657 sctp_cmd_seq_t *commands) 658 { 659 struct sctp_chunk *chunk = arg; 660 struct sctp_association *new_asoc; 661 sctp_init_chunk_t *peer_init; 662 struct sctp_chunk *repl; 663 struct sctp_ulpevent *ev, *ai_ev = NULL; 664 int error = 0; 665 struct sctp_chunk *err_chk_p; 666 struct sock *sk; 667 668 /* If the packet is an OOTB packet which is temporarily on the 669 * control endpoint, respond with an ABORT. 670 */ 671 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 672 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 673 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 674 } 675 676 /* Make sure that the COOKIE_ECHO chunk has a valid length. 677 * In this case, we check that we have enough for at least a 678 * chunk header. More detailed verification is done 679 * in sctp_unpack_cookie(). 680 */ 681 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 682 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 683 684 /* If the endpoint is not listening or if the number of associations 685 * on the TCP-style socket exceed the max backlog, respond with an 686 * ABORT. 687 */ 688 sk = ep->base.sk; 689 if (!sctp_sstate(sk, LISTENING) || 690 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 691 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 692 693 /* "Decode" the chunk. We have no optional parameters so we 694 * are in good shape. 695 */ 696 chunk->subh.cookie_hdr = 697 (struct sctp_signed_cookie *)chunk->skb->data; 698 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 699 sizeof(sctp_chunkhdr_t))) 700 goto nomem; 701 702 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 703 * "Z" will reply with a COOKIE ACK chunk after building a TCB 704 * and moving to the ESTABLISHED state. 705 */ 706 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 707 &err_chk_p); 708 709 /* FIXME: 710 * If the re-build failed, what is the proper error path 711 * from here? 712 * 713 * [We should abort the association. --piggy] 714 */ 715 if (!new_asoc) { 716 /* FIXME: Several errors are possible. A bad cookie should 717 * be silently discarded, but think about logging it too. 718 */ 719 switch (error) { 720 case -SCTP_IERROR_NOMEM: 721 goto nomem; 722 723 case -SCTP_IERROR_STALE_COOKIE: 724 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 725 err_chk_p); 726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 727 728 case -SCTP_IERROR_BAD_SIG: 729 default: 730 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 731 } 732 } 733 734 735 /* Delay state machine commands until later. 736 * 737 * Re-build the bind address for the association is done in 738 * the sctp_unpack_cookie() already. 739 */ 740 /* This is a brand-new association, so these are not yet side 741 * effects--it is safe to run them here. 742 */ 743 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 744 745 if (!sctp_process_init(new_asoc, chunk, 746 &chunk->subh.cookie_hdr->c.peer_addr, 747 peer_init, GFP_ATOMIC)) 748 goto nomem_init; 749 750 /* SCTP-AUTH: Now that we've populate required fields in 751 * sctp_process_init, set up the assocaition shared keys as 752 * necessary so that we can potentially authenticate the ACK 753 */ 754 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 755 if (error) 756 goto nomem_init; 757 758 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 759 * is supposed to be authenticated and we have to do delayed 760 * authentication. We've just recreated the association using 761 * the information in the cookie and now it's much easier to 762 * do the authentication. 763 */ 764 if (chunk->auth_chunk) { 765 struct sctp_chunk auth; 766 sctp_ierror_t ret; 767 768 /* set-up our fake chunk so that we can process it */ 769 auth.skb = chunk->auth_chunk; 770 auth.asoc = chunk->asoc; 771 auth.sctp_hdr = chunk->sctp_hdr; 772 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 773 sizeof(sctp_chunkhdr_t)); 774 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 775 auth.transport = chunk->transport; 776 777 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 778 779 /* We can now safely free the auth_chunk clone */ 780 kfree_skb(chunk->auth_chunk); 781 782 if (ret != SCTP_IERROR_NO_ERROR) { 783 sctp_association_free(new_asoc); 784 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 785 } 786 } 787 788 repl = sctp_make_cookie_ack(new_asoc, chunk); 789 if (!repl) 790 goto nomem_init; 791 792 /* RFC 2960 5.1 Normal Establishment of an Association 793 * 794 * D) IMPLEMENTATION NOTE: An implementation may choose to 795 * send the Communication Up notification to the SCTP user 796 * upon reception of a valid COOKIE ECHO chunk. 797 */ 798 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 799 new_asoc->c.sinit_num_ostreams, 800 new_asoc->c.sinit_max_instreams, 801 NULL, GFP_ATOMIC); 802 if (!ev) 803 goto nomem_ev; 804 805 /* Sockets API Draft Section 5.3.1.6 806 * When a peer sends a Adaptation Layer Indication parameter , SCTP 807 * delivers this notification to inform the application that of the 808 * peers requested adaptation layer. 809 */ 810 if (new_asoc->peer.adaptation_ind) { 811 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 812 GFP_ATOMIC); 813 if (!ai_ev) 814 goto nomem_aiev; 815 } 816 817 /* Add all the state machine commands now since we've created 818 * everything. This way we don't introduce memory corruptions 819 * during side-effect processing and correclty count established 820 * associations. 821 */ 822 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 823 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 824 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 825 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 826 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 827 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 828 829 if (new_asoc->autoclose) 830 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 831 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 832 833 /* This will send the COOKIE ACK */ 834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 835 836 /* Queue the ASSOC_CHANGE event */ 837 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 838 839 /* Send up the Adaptation Layer Indication event */ 840 if (ai_ev) 841 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 842 SCTP_ULPEVENT(ai_ev)); 843 844 return SCTP_DISPOSITION_CONSUME; 845 846 nomem_aiev: 847 sctp_ulpevent_free(ev); 848 nomem_ev: 849 sctp_chunk_free(repl); 850 nomem_init: 851 sctp_association_free(new_asoc); 852 nomem: 853 return SCTP_DISPOSITION_NOMEM; 854 } 855 856 /* 857 * Respond to a normal COOKIE ACK chunk. 858 * We are the side that is being asked for an association. 859 * 860 * RFC 2960 5.1 Normal Establishment of an Association 861 * 862 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 863 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 864 * timer. It may also notify its ULP about the successful 865 * establishment of the association with a Communication Up 866 * notification (see Section 10). 867 * 868 * Verification Tag: 869 * Inputs 870 * (endpoint, asoc, chunk) 871 * 872 * Outputs 873 * (asoc, reply_msg, msg_up, timers, counters) 874 * 875 * The return value is the disposition of the chunk. 876 */ 877 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 878 const struct sctp_endpoint *ep, 879 const struct sctp_association *asoc, 880 const sctp_subtype_t type, void *arg, 881 sctp_cmd_seq_t *commands) 882 { 883 struct sctp_chunk *chunk = arg; 884 struct sctp_ulpevent *ev; 885 886 if (!sctp_vtag_verify(chunk, asoc)) 887 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 888 889 /* Verify that the chunk length for the COOKIE-ACK is OK. 890 * If we don't do this, any bundled chunks may be junked. 891 */ 892 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 893 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 894 commands); 895 896 /* Reset init error count upon receipt of COOKIE-ACK, 897 * to avoid problems with the managemement of this 898 * counter in stale cookie situations when a transition back 899 * from the COOKIE-ECHOED state to the COOKIE-WAIT 900 * state is performed. 901 */ 902 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 903 904 /* RFC 2960 5.1 Normal Establishment of an Association 905 * 906 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 907 * from the COOKIE-ECHOED state to the ESTABLISHED state, 908 * stopping the T1-cookie timer. 909 */ 910 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 911 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 912 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 913 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 914 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 915 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 916 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 917 if (asoc->autoclose) 918 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 919 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 920 921 /* It may also notify its ULP about the successful 922 * establishment of the association with a Communication Up 923 * notification (see Section 10). 924 */ 925 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 926 0, asoc->c.sinit_num_ostreams, 927 asoc->c.sinit_max_instreams, 928 NULL, GFP_ATOMIC); 929 930 if (!ev) 931 goto nomem; 932 933 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 934 935 /* Sockets API Draft Section 5.3.1.6 936 * When a peer sends a Adaptation Layer Indication parameter , SCTP 937 * delivers this notification to inform the application that of the 938 * peers requested adaptation layer. 939 */ 940 if (asoc->peer.adaptation_ind) { 941 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 942 if (!ev) 943 goto nomem; 944 945 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 946 SCTP_ULPEVENT(ev)); 947 } 948 949 return SCTP_DISPOSITION_CONSUME; 950 nomem: 951 return SCTP_DISPOSITION_NOMEM; 952 } 953 954 /* Generate and sendout a heartbeat packet. */ 955 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 956 const struct sctp_association *asoc, 957 const sctp_subtype_t type, 958 void *arg, 959 sctp_cmd_seq_t *commands) 960 { 961 struct sctp_transport *transport = (struct sctp_transport *) arg; 962 struct sctp_chunk *reply; 963 964 /* Send a heartbeat to our peer. */ 965 reply = sctp_make_heartbeat(asoc, transport); 966 if (!reply) 967 return SCTP_DISPOSITION_NOMEM; 968 969 /* Set rto_pending indicating that an RTT measurement 970 * is started with this heartbeat chunk. 971 */ 972 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 973 SCTP_TRANSPORT(transport)); 974 975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 976 return SCTP_DISPOSITION_CONSUME; 977 } 978 979 /* Generate a HEARTBEAT packet on the given transport. */ 980 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 981 const struct sctp_endpoint *ep, 982 const struct sctp_association *asoc, 983 const sctp_subtype_t type, 984 void *arg, 985 sctp_cmd_seq_t *commands) 986 { 987 struct sctp_transport *transport = (struct sctp_transport *) arg; 988 989 if (asoc->overall_error_count >= asoc->max_retrans) { 990 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 991 SCTP_ERROR(ETIMEDOUT)); 992 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 993 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 994 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 995 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 996 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 997 return SCTP_DISPOSITION_DELETE_TCB; 998 } 999 1000 /* Section 3.3.5. 1001 * The Sender-specific Heartbeat Info field should normally include 1002 * information about the sender's current time when this HEARTBEAT 1003 * chunk is sent and the destination transport address to which this 1004 * HEARTBEAT is sent (see Section 8.3). 1005 */ 1006 1007 if (transport->param_flags & SPP_HB_ENABLE) { 1008 if (SCTP_DISPOSITION_NOMEM == 1009 sctp_sf_heartbeat(ep, asoc, type, arg, 1010 commands)) 1011 return SCTP_DISPOSITION_NOMEM; 1012 1013 /* Set transport error counter and association error counter 1014 * when sending heartbeat. 1015 */ 1016 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1017 SCTP_TRANSPORT(transport)); 1018 } 1019 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1020 SCTP_TRANSPORT(transport)); 1021 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1022 SCTP_TRANSPORT(transport)); 1023 1024 return SCTP_DISPOSITION_CONSUME; 1025 } 1026 1027 /* 1028 * Process an heartbeat request. 1029 * 1030 * Section: 8.3 Path Heartbeat 1031 * The receiver of the HEARTBEAT should immediately respond with a 1032 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1033 * from the received HEARTBEAT chunk. 1034 * 1035 * Verification Tag: 8.5 Verification Tag [Normal verification] 1036 * When receiving an SCTP packet, the endpoint MUST ensure that the 1037 * value in the Verification Tag field of the received SCTP packet 1038 * matches its own Tag. If the received Verification Tag value does not 1039 * match the receiver's own tag value, the receiver shall silently 1040 * discard the packet and shall not process it any further except for 1041 * those cases listed in Section 8.5.1 below. 1042 * 1043 * Inputs 1044 * (endpoint, asoc, chunk) 1045 * 1046 * Outputs 1047 * (asoc, reply_msg, msg_up, timers, counters) 1048 * 1049 * The return value is the disposition of the chunk. 1050 */ 1051 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1052 const struct sctp_endpoint *ep, 1053 const struct sctp_association *asoc, 1054 const sctp_subtype_t type, 1055 void *arg, 1056 sctp_cmd_seq_t *commands) 1057 { 1058 sctp_paramhdr_t *param_hdr; 1059 struct sctp_chunk *chunk = arg; 1060 struct sctp_chunk *reply; 1061 size_t paylen = 0; 1062 1063 if (!sctp_vtag_verify(chunk, asoc)) 1064 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1065 1066 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1067 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1068 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1069 commands); 1070 1071 /* 8.3 The receiver of the HEARTBEAT should immediately 1072 * respond with a HEARTBEAT ACK that contains the Heartbeat 1073 * Information field copied from the received HEARTBEAT chunk. 1074 */ 1075 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1076 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1077 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1078 1079 if (ntohs(param_hdr->length) > paylen) 1080 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1081 param_hdr, commands); 1082 1083 if (!pskb_pull(chunk->skb, paylen)) 1084 goto nomem; 1085 1086 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1087 if (!reply) 1088 goto nomem; 1089 1090 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1091 return SCTP_DISPOSITION_CONSUME; 1092 1093 nomem: 1094 return SCTP_DISPOSITION_NOMEM; 1095 } 1096 1097 /* 1098 * Process the returning HEARTBEAT ACK. 1099 * 1100 * Section: 8.3 Path Heartbeat 1101 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1102 * should clear the error counter of the destination transport 1103 * address to which the HEARTBEAT was sent, and mark the destination 1104 * transport address as active if it is not so marked. The endpoint may 1105 * optionally report to the upper layer when an inactive destination 1106 * address is marked as active due to the reception of the latest 1107 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1108 * clear the association overall error count as well (as defined 1109 * in section 8.1). 1110 * 1111 * The receiver of the HEARTBEAT ACK should also perform an RTT 1112 * measurement for that destination transport address using the time 1113 * value carried in the HEARTBEAT ACK chunk. 1114 * 1115 * Verification Tag: 8.5 Verification Tag [Normal verification] 1116 * 1117 * Inputs 1118 * (endpoint, asoc, chunk) 1119 * 1120 * Outputs 1121 * (asoc, reply_msg, msg_up, timers, counters) 1122 * 1123 * The return value is the disposition of the chunk. 1124 */ 1125 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1126 const struct sctp_endpoint *ep, 1127 const struct sctp_association *asoc, 1128 const sctp_subtype_t type, 1129 void *arg, 1130 sctp_cmd_seq_t *commands) 1131 { 1132 struct sctp_chunk *chunk = arg; 1133 union sctp_addr from_addr; 1134 struct sctp_transport *link; 1135 sctp_sender_hb_info_t *hbinfo; 1136 unsigned long max_interval; 1137 1138 if (!sctp_vtag_verify(chunk, asoc)) 1139 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1140 1141 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1142 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1143 sizeof(sctp_sender_hb_info_t))) 1144 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1145 commands); 1146 1147 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1148 /* Make sure that the length of the parameter is what we expect */ 1149 if (ntohs(hbinfo->param_hdr.length) != 1150 sizeof(sctp_sender_hb_info_t)) { 1151 return SCTP_DISPOSITION_DISCARD; 1152 } 1153 1154 from_addr = hbinfo->daddr; 1155 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1156 1157 /* This should never happen, but lets log it if so. */ 1158 if (unlikely(!link)) { 1159 if (from_addr.sa.sa_family == AF_INET6) { 1160 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1161 __func__, 1162 asoc, 1163 &from_addr.v6.sin6_addr); 1164 } else { 1165 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1166 __func__, 1167 asoc, 1168 &from_addr.v4.sin_addr.s_addr); 1169 } 1170 return SCTP_DISPOSITION_DISCARD; 1171 } 1172 1173 /* Validate the 64-bit random nonce. */ 1174 if (hbinfo->hb_nonce != link->hb_nonce) 1175 return SCTP_DISPOSITION_DISCARD; 1176 1177 max_interval = link->hbinterval + link->rto; 1178 1179 /* Check if the timestamp looks valid. */ 1180 if (time_after(hbinfo->sent_at, jiffies) || 1181 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1182 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1183 "received for transport: %p\n", 1184 __func__, link); 1185 return SCTP_DISPOSITION_DISCARD; 1186 } 1187 1188 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1189 * the HEARTBEAT should clear the error counter of the 1190 * destination transport address to which the HEARTBEAT was 1191 * sent and mark the destination transport address as active if 1192 * it is not so marked. 1193 */ 1194 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1195 1196 return SCTP_DISPOSITION_CONSUME; 1197 } 1198 1199 /* Helper function to send out an abort for the restart 1200 * condition. 1201 */ 1202 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1203 struct sctp_chunk *init, 1204 sctp_cmd_seq_t *commands) 1205 { 1206 int len; 1207 struct sctp_packet *pkt; 1208 union sctp_addr_param *addrparm; 1209 struct sctp_errhdr *errhdr; 1210 struct sctp_endpoint *ep; 1211 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1212 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1213 1214 /* Build the error on the stack. We are way to malloc crazy 1215 * throughout the code today. 1216 */ 1217 errhdr = (struct sctp_errhdr *)buffer; 1218 addrparm = (union sctp_addr_param *)errhdr->variable; 1219 1220 /* Copy into a parm format. */ 1221 len = af->to_addr_param(ssa, addrparm); 1222 len += sizeof(sctp_errhdr_t); 1223 1224 errhdr->cause = SCTP_ERROR_RESTART; 1225 errhdr->length = htons(len); 1226 1227 /* Assign to the control socket. */ 1228 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1229 1230 /* Association is NULL since this may be a restart attack and we 1231 * want to send back the attacker's vtag. 1232 */ 1233 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1234 1235 if (!pkt) 1236 goto out; 1237 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1238 1239 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1240 1241 /* Discard the rest of the inbound packet. */ 1242 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1243 1244 out: 1245 /* Even if there is no memory, treat as a failure so 1246 * the packet will get dropped. 1247 */ 1248 return 0; 1249 } 1250 1251 static bool list_has_sctp_addr(const struct list_head *list, 1252 union sctp_addr *ipaddr) 1253 { 1254 struct sctp_transport *addr; 1255 1256 list_for_each_entry(addr, list, transports) { 1257 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1258 return true; 1259 } 1260 1261 return false; 1262 } 1263 /* A restart is occurring, check to make sure no new addresses 1264 * are being added as we may be under a takeover attack. 1265 */ 1266 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1267 const struct sctp_association *asoc, 1268 struct sctp_chunk *init, 1269 sctp_cmd_seq_t *commands) 1270 { 1271 struct net *net = sock_net(new_asoc->base.sk); 1272 struct sctp_transport *new_addr; 1273 int ret = 1; 1274 1275 /* Implementor's Guide - Section 5.2.2 1276 * ... 1277 * Before responding the endpoint MUST check to see if the 1278 * unexpected INIT adds new addresses to the association. If new 1279 * addresses are added to the association, the endpoint MUST respond 1280 * with an ABORT.. 1281 */ 1282 1283 /* Search through all current addresses and make sure 1284 * we aren't adding any new ones. 1285 */ 1286 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1287 transports) { 1288 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1289 &new_addr->ipaddr)) { 1290 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1291 commands); 1292 ret = 0; 1293 break; 1294 } 1295 } 1296 1297 /* Return success if all addresses were found. */ 1298 return ret; 1299 } 1300 1301 /* Populate the verification/tie tags based on overlapping INIT 1302 * scenario. 1303 * 1304 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1305 */ 1306 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1307 const struct sctp_association *asoc) 1308 { 1309 switch (asoc->state) { 1310 1311 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1312 1313 case SCTP_STATE_COOKIE_WAIT: 1314 new_asoc->c.my_vtag = asoc->c.my_vtag; 1315 new_asoc->c.my_ttag = asoc->c.my_vtag; 1316 new_asoc->c.peer_ttag = 0; 1317 break; 1318 1319 case SCTP_STATE_COOKIE_ECHOED: 1320 new_asoc->c.my_vtag = asoc->c.my_vtag; 1321 new_asoc->c.my_ttag = asoc->c.my_vtag; 1322 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1323 break; 1324 1325 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1326 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1327 */ 1328 default: 1329 new_asoc->c.my_ttag = asoc->c.my_vtag; 1330 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1331 break; 1332 } 1333 1334 /* Other parameters for the endpoint SHOULD be copied from the 1335 * existing parameters of the association (e.g. number of 1336 * outbound streams) into the INIT ACK and cookie. 1337 */ 1338 new_asoc->rwnd = asoc->rwnd; 1339 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1340 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1341 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1342 } 1343 1344 /* 1345 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1346 * handling action. 1347 * 1348 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1349 * 1350 * Returns value representing action to be taken. These action values 1351 * correspond to Action/Description values in RFC 2960, Table 2. 1352 */ 1353 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1354 const struct sctp_association *asoc) 1355 { 1356 /* In this case, the peer may have restarted. */ 1357 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1358 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1359 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1360 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1361 return 'A'; 1362 1363 /* Collision case B. */ 1364 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1365 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1366 (0 == asoc->c.peer_vtag))) { 1367 return 'B'; 1368 } 1369 1370 /* Collision case D. */ 1371 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1372 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1373 return 'D'; 1374 1375 /* Collision case C. */ 1376 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1377 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1378 (0 == new_asoc->c.my_ttag) && 1379 (0 == new_asoc->c.peer_ttag)) 1380 return 'C'; 1381 1382 /* No match to any of the special cases; discard this packet. */ 1383 return 'E'; 1384 } 1385 1386 /* Common helper routine for both duplicate and simulataneous INIT 1387 * chunk handling. 1388 */ 1389 static sctp_disposition_t sctp_sf_do_unexpected_init( 1390 struct net *net, 1391 const struct sctp_endpoint *ep, 1392 const struct sctp_association *asoc, 1393 const sctp_subtype_t type, 1394 void *arg, sctp_cmd_seq_t *commands) 1395 { 1396 sctp_disposition_t retval; 1397 struct sctp_chunk *chunk = arg; 1398 struct sctp_chunk *repl; 1399 struct sctp_association *new_asoc; 1400 struct sctp_chunk *err_chunk; 1401 struct sctp_packet *packet; 1402 sctp_unrecognized_param_t *unk_param; 1403 int len; 1404 1405 /* 6.10 Bundling 1406 * An endpoint MUST NOT bundle INIT, INIT ACK or 1407 * SHUTDOWN COMPLETE with any other chunks. 1408 * 1409 * IG Section 2.11.2 1410 * Furthermore, we require that the receiver of an INIT chunk MUST 1411 * enforce these rules by silently discarding an arriving packet 1412 * with an INIT chunk that is bundled with other chunks. 1413 */ 1414 if (!chunk->singleton) 1415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1416 1417 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1418 * Tag. 1419 */ 1420 if (chunk->sctp_hdr->vtag != 0) 1421 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1422 1423 /* Make sure that the INIT chunk has a valid length. 1424 * In this case, we generate a protocol violation since we have 1425 * an association established. 1426 */ 1427 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1429 commands); 1430 /* Grab the INIT header. */ 1431 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1432 1433 /* Tag the variable length parameters. */ 1434 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1435 1436 /* Verify the INIT chunk before processing it. */ 1437 err_chunk = NULL; 1438 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 1439 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1440 &err_chunk)) { 1441 /* This chunk contains fatal error. It is to be discarded. 1442 * Send an ABORT, with causes if there is any. 1443 */ 1444 if (err_chunk) { 1445 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1446 (__u8 *)(err_chunk->chunk_hdr) + 1447 sizeof(sctp_chunkhdr_t), 1448 ntohs(err_chunk->chunk_hdr->length) - 1449 sizeof(sctp_chunkhdr_t)); 1450 1451 if (packet) { 1452 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1453 SCTP_PACKET(packet)); 1454 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1455 retval = SCTP_DISPOSITION_CONSUME; 1456 } else { 1457 retval = SCTP_DISPOSITION_NOMEM; 1458 } 1459 goto cleanup; 1460 } else { 1461 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1462 commands); 1463 } 1464 } 1465 1466 /* 1467 * Other parameters for the endpoint SHOULD be copied from the 1468 * existing parameters of the association (e.g. number of 1469 * outbound streams) into the INIT ACK and cookie. 1470 * FIXME: We are copying parameters from the endpoint not the 1471 * association. 1472 */ 1473 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1474 if (!new_asoc) 1475 goto nomem; 1476 1477 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1478 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1479 goto nomem; 1480 1481 /* In the outbound INIT ACK the endpoint MUST copy its current 1482 * Verification Tag and Peers Verification tag into a reserved 1483 * place (local tie-tag and per tie-tag) within the state cookie. 1484 */ 1485 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1486 (sctp_init_chunk_t *)chunk->chunk_hdr, 1487 GFP_ATOMIC)) 1488 goto nomem; 1489 1490 /* Make sure no new addresses are being added during the 1491 * restart. Do not do this check for COOKIE-WAIT state, 1492 * since there are no peer addresses to check against. 1493 * Upon return an ABORT will have been sent if needed. 1494 */ 1495 if (!sctp_state(asoc, COOKIE_WAIT)) { 1496 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1497 commands)) { 1498 retval = SCTP_DISPOSITION_CONSUME; 1499 goto nomem_retval; 1500 } 1501 } 1502 1503 sctp_tietags_populate(new_asoc, asoc); 1504 1505 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1506 1507 /* If there are errors need to be reported for unknown parameters, 1508 * make sure to reserve enough room in the INIT ACK for them. 1509 */ 1510 len = 0; 1511 if (err_chunk) { 1512 len = ntohs(err_chunk->chunk_hdr->length) - 1513 sizeof(sctp_chunkhdr_t); 1514 } 1515 1516 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1517 if (!repl) 1518 goto nomem; 1519 1520 /* If there are errors need to be reported for unknown parameters, 1521 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1522 * parameter. 1523 */ 1524 if (err_chunk) { 1525 /* Get the "Unrecognized parameter" parameter(s) out of the 1526 * ERROR chunk generated by sctp_verify_init(). Since the 1527 * error cause code for "unknown parameter" and the 1528 * "Unrecognized parameter" type is the same, we can 1529 * construct the parameters in INIT ACK by copying the 1530 * ERROR causes over. 1531 */ 1532 unk_param = (sctp_unrecognized_param_t *) 1533 ((__u8 *)(err_chunk->chunk_hdr) + 1534 sizeof(sctp_chunkhdr_t)); 1535 /* Replace the cause code with the "Unrecognized parameter" 1536 * parameter type. 1537 */ 1538 sctp_addto_chunk(repl, len, unk_param); 1539 } 1540 1541 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1542 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1543 1544 /* 1545 * Note: After sending out INIT ACK with the State Cookie parameter, 1546 * "Z" MUST NOT allocate any resources for this new association. 1547 * Otherwise, "Z" will be vulnerable to resource attacks. 1548 */ 1549 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1550 retval = SCTP_DISPOSITION_CONSUME; 1551 1552 return retval; 1553 1554 nomem: 1555 retval = SCTP_DISPOSITION_NOMEM; 1556 nomem_retval: 1557 if (new_asoc) 1558 sctp_association_free(new_asoc); 1559 cleanup: 1560 if (err_chunk) 1561 sctp_chunk_free(err_chunk); 1562 return retval; 1563 } 1564 1565 /* 1566 * Handle simultaneous INIT. 1567 * This means we started an INIT and then we got an INIT request from 1568 * our peer. 1569 * 1570 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1571 * This usually indicates an initialization collision, i.e., each 1572 * endpoint is attempting, at about the same time, to establish an 1573 * association with the other endpoint. 1574 * 1575 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1576 * endpoint MUST respond with an INIT ACK using the same parameters it 1577 * sent in its original INIT chunk (including its Verification Tag, 1578 * unchanged). These original parameters are combined with those from the 1579 * newly received INIT chunk. The endpoint shall also generate a State 1580 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1581 * INIT to calculate the State Cookie. 1582 * 1583 * After that, the endpoint MUST NOT change its state, the T1-init 1584 * timer shall be left running and the corresponding TCB MUST NOT be 1585 * destroyed. The normal procedures for handling State Cookies when 1586 * a TCB exists will resolve the duplicate INITs to a single association. 1587 * 1588 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1589 * its Tie-Tags with the Tag information of itself and its peer (see 1590 * section 5.2.2 for a description of the Tie-Tags). 1591 * 1592 * Verification Tag: Not explicit, but an INIT can not have a valid 1593 * verification tag, so we skip the check. 1594 * 1595 * Inputs 1596 * (endpoint, asoc, chunk) 1597 * 1598 * Outputs 1599 * (asoc, reply_msg, msg_up, timers, counters) 1600 * 1601 * The return value is the disposition of the chunk. 1602 */ 1603 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1604 const struct sctp_endpoint *ep, 1605 const struct sctp_association *asoc, 1606 const sctp_subtype_t type, 1607 void *arg, 1608 sctp_cmd_seq_t *commands) 1609 { 1610 /* Call helper to do the real work for both simulataneous and 1611 * duplicate INIT chunk handling. 1612 */ 1613 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1614 } 1615 1616 /* 1617 * Handle duplicated INIT messages. These are usually delayed 1618 * restransmissions. 1619 * 1620 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1621 * COOKIE-ECHOED and COOKIE-WAIT 1622 * 1623 * Unless otherwise stated, upon reception of an unexpected INIT for 1624 * this association, the endpoint shall generate an INIT ACK with a 1625 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1626 * current Verification Tag and peer's Verification Tag into a reserved 1627 * place within the state cookie. We shall refer to these locations as 1628 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1629 * containing this INIT ACK MUST carry a Verification Tag value equal to 1630 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1631 * MUST contain a new Initiation Tag (randomly generated see Section 1632 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1633 * existing parameters of the association (e.g. number of outbound 1634 * streams) into the INIT ACK and cookie. 1635 * 1636 * After sending out the INIT ACK, the endpoint shall take no further 1637 * actions, i.e., the existing association, including its current state, 1638 * and the corresponding TCB MUST NOT be changed. 1639 * 1640 * Note: Only when a TCB exists and the association is not in a COOKIE- 1641 * WAIT state are the Tie-Tags populated. For a normal association INIT 1642 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1643 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1644 * State Cookie are populated as specified in section 5.2.1. 1645 * 1646 * Verification Tag: Not specified, but an INIT has no way of knowing 1647 * what the verification tag could be, so we ignore it. 1648 * 1649 * Inputs 1650 * (endpoint, asoc, chunk) 1651 * 1652 * Outputs 1653 * (asoc, reply_msg, msg_up, timers, counters) 1654 * 1655 * The return value is the disposition of the chunk. 1656 */ 1657 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1658 const struct sctp_endpoint *ep, 1659 const struct sctp_association *asoc, 1660 const sctp_subtype_t type, 1661 void *arg, 1662 sctp_cmd_seq_t *commands) 1663 { 1664 /* Call helper to do the real work for both simulataneous and 1665 * duplicate INIT chunk handling. 1666 */ 1667 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1668 } 1669 1670 1671 /* 1672 * Unexpected INIT-ACK handler. 1673 * 1674 * Section 5.2.3 1675 * If an INIT ACK received by an endpoint in any state other than the 1676 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1677 * An unexpected INIT ACK usually indicates the processing of an old or 1678 * duplicated INIT chunk. 1679 */ 1680 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1681 const struct sctp_endpoint *ep, 1682 const struct sctp_association *asoc, 1683 const sctp_subtype_t type, 1684 void *arg, sctp_cmd_seq_t *commands) 1685 { 1686 /* Per the above section, we'll discard the chunk if we have an 1687 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1688 */ 1689 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1690 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1691 else 1692 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1693 } 1694 1695 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1696 * 1697 * Section 5.2.4 1698 * A) In this case, the peer may have restarted. 1699 */ 1700 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1701 const struct sctp_endpoint *ep, 1702 const struct sctp_association *asoc, 1703 struct sctp_chunk *chunk, 1704 sctp_cmd_seq_t *commands, 1705 struct sctp_association *new_asoc) 1706 { 1707 sctp_init_chunk_t *peer_init; 1708 struct sctp_ulpevent *ev; 1709 struct sctp_chunk *repl; 1710 struct sctp_chunk *err; 1711 sctp_disposition_t disposition; 1712 1713 /* new_asoc is a brand-new association, so these are not yet 1714 * side effects--it is safe to run them here. 1715 */ 1716 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1717 1718 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1719 GFP_ATOMIC)) 1720 goto nomem; 1721 1722 /* Make sure no new addresses are being added during the 1723 * restart. Though this is a pretty complicated attack 1724 * since you'd have to get inside the cookie. 1725 */ 1726 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1727 return SCTP_DISPOSITION_CONSUME; 1728 } 1729 1730 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1731 * the peer has restarted (Action A), it MUST NOT setup a new 1732 * association but instead resend the SHUTDOWN ACK and send an ERROR 1733 * chunk with a "Cookie Received while Shutting Down" error cause to 1734 * its peer. 1735 */ 1736 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1737 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1738 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1739 chunk, commands); 1740 if (SCTP_DISPOSITION_NOMEM == disposition) 1741 goto nomem; 1742 1743 err = sctp_make_op_error(asoc, chunk, 1744 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1745 NULL, 0, 0); 1746 if (err) 1747 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1748 SCTP_CHUNK(err)); 1749 1750 return SCTP_DISPOSITION_CONSUME; 1751 } 1752 1753 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1754 * data. Consider the optional choice of resending of this data. 1755 */ 1756 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1757 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1758 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1759 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1760 1761 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1762 * and ASCONF-ACK cache. 1763 */ 1764 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1765 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1766 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1767 1768 repl = sctp_make_cookie_ack(new_asoc, chunk); 1769 if (!repl) 1770 goto nomem; 1771 1772 /* Report association restart to upper layer. */ 1773 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1774 new_asoc->c.sinit_num_ostreams, 1775 new_asoc->c.sinit_max_instreams, 1776 NULL, GFP_ATOMIC); 1777 if (!ev) 1778 goto nomem_ev; 1779 1780 /* Update the content of current association. */ 1781 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1782 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1783 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1784 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1785 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1786 return SCTP_DISPOSITION_CONSUME; 1787 1788 nomem_ev: 1789 sctp_chunk_free(repl); 1790 nomem: 1791 return SCTP_DISPOSITION_NOMEM; 1792 } 1793 1794 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1795 * 1796 * Section 5.2.4 1797 * B) In this case, both sides may be attempting to start an association 1798 * at about the same time but the peer endpoint started its INIT 1799 * after responding to the local endpoint's INIT 1800 */ 1801 /* This case represents an initialization collision. */ 1802 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1803 const struct sctp_endpoint *ep, 1804 const struct sctp_association *asoc, 1805 struct sctp_chunk *chunk, 1806 sctp_cmd_seq_t *commands, 1807 struct sctp_association *new_asoc) 1808 { 1809 sctp_init_chunk_t *peer_init; 1810 struct sctp_chunk *repl; 1811 1812 /* new_asoc is a brand-new association, so these are not yet 1813 * side effects--it is safe to run them here. 1814 */ 1815 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1816 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1817 GFP_ATOMIC)) 1818 goto nomem; 1819 1820 /* Update the content of current association. */ 1821 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1822 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1823 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1824 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1825 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1826 1827 repl = sctp_make_cookie_ack(new_asoc, chunk); 1828 if (!repl) 1829 goto nomem; 1830 1831 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1832 1833 /* RFC 2960 5.1 Normal Establishment of an Association 1834 * 1835 * D) IMPLEMENTATION NOTE: An implementation may choose to 1836 * send the Communication Up notification to the SCTP user 1837 * upon reception of a valid COOKIE ECHO chunk. 1838 * 1839 * Sadly, this needs to be implemented as a side-effect, because 1840 * we are not guaranteed to have set the association id of the real 1841 * association and so these notifications need to be delayed until 1842 * the association id is allocated. 1843 */ 1844 1845 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1846 1847 /* Sockets API Draft Section 5.3.1.6 1848 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1849 * delivers this notification to inform the application that of the 1850 * peers requested adaptation layer. 1851 * 1852 * This also needs to be done as a side effect for the same reason as 1853 * above. 1854 */ 1855 if (asoc->peer.adaptation_ind) 1856 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1857 1858 return SCTP_DISPOSITION_CONSUME; 1859 1860 nomem: 1861 return SCTP_DISPOSITION_NOMEM; 1862 } 1863 1864 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1865 * 1866 * Section 5.2.4 1867 * C) In this case, the local endpoint's cookie has arrived late. 1868 * Before it arrived, the local endpoint sent an INIT and received an 1869 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1870 * but a new tag of its own. 1871 */ 1872 /* This case represents an initialization collision. */ 1873 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1874 const struct sctp_endpoint *ep, 1875 const struct sctp_association *asoc, 1876 struct sctp_chunk *chunk, 1877 sctp_cmd_seq_t *commands, 1878 struct sctp_association *new_asoc) 1879 { 1880 /* The cookie should be silently discarded. 1881 * The endpoint SHOULD NOT change states and should leave 1882 * any timers running. 1883 */ 1884 return SCTP_DISPOSITION_DISCARD; 1885 } 1886 1887 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1888 * 1889 * Section 5.2.4 1890 * 1891 * D) When both local and remote tags match the endpoint should always 1892 * enter the ESTABLISHED state, if it has not already done so. 1893 */ 1894 /* This case represents an initialization collision. */ 1895 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1896 const struct sctp_endpoint *ep, 1897 const struct sctp_association *asoc, 1898 struct sctp_chunk *chunk, 1899 sctp_cmd_seq_t *commands, 1900 struct sctp_association *new_asoc) 1901 { 1902 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1903 struct sctp_chunk *repl; 1904 1905 /* Clarification from Implementor's Guide: 1906 * D) When both local and remote tags match the endpoint should 1907 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1908 * It should stop any cookie timer that may be running and send 1909 * a COOKIE ACK. 1910 */ 1911 1912 /* Don't accidentally move back into established state. */ 1913 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1914 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1915 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1916 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1917 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1918 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1919 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1920 SCTP_NULL()); 1921 1922 /* RFC 2960 5.1 Normal Establishment of an Association 1923 * 1924 * D) IMPLEMENTATION NOTE: An implementation may choose 1925 * to send the Communication Up notification to the 1926 * SCTP user upon reception of a valid COOKIE 1927 * ECHO chunk. 1928 */ 1929 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1930 SCTP_COMM_UP, 0, 1931 asoc->c.sinit_num_ostreams, 1932 asoc->c.sinit_max_instreams, 1933 NULL, GFP_ATOMIC); 1934 if (!ev) 1935 goto nomem; 1936 1937 /* Sockets API Draft Section 5.3.1.6 1938 * When a peer sends a Adaptation Layer Indication parameter, 1939 * SCTP delivers this notification to inform the application 1940 * that of the peers requested adaptation layer. 1941 */ 1942 if (asoc->peer.adaptation_ind) { 1943 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1944 GFP_ATOMIC); 1945 if (!ai_ev) 1946 goto nomem; 1947 1948 } 1949 } 1950 1951 repl = sctp_make_cookie_ack(new_asoc, chunk); 1952 if (!repl) 1953 goto nomem; 1954 1955 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1956 1957 if (ev) 1958 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1959 SCTP_ULPEVENT(ev)); 1960 if (ai_ev) 1961 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1962 SCTP_ULPEVENT(ai_ev)); 1963 1964 return SCTP_DISPOSITION_CONSUME; 1965 1966 nomem: 1967 if (ai_ev) 1968 sctp_ulpevent_free(ai_ev); 1969 if (ev) 1970 sctp_ulpevent_free(ev); 1971 return SCTP_DISPOSITION_NOMEM; 1972 } 1973 1974 /* 1975 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1976 * chunk was retransmitted and then delayed in the network. 1977 * 1978 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1979 * 1980 * Verification Tag: None. Do cookie validation. 1981 * 1982 * Inputs 1983 * (endpoint, asoc, chunk) 1984 * 1985 * Outputs 1986 * (asoc, reply_msg, msg_up, timers, counters) 1987 * 1988 * The return value is the disposition of the chunk. 1989 */ 1990 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1991 const struct sctp_endpoint *ep, 1992 const struct sctp_association *asoc, 1993 const sctp_subtype_t type, 1994 void *arg, 1995 sctp_cmd_seq_t *commands) 1996 { 1997 sctp_disposition_t retval; 1998 struct sctp_chunk *chunk = arg; 1999 struct sctp_association *new_asoc; 2000 int error = 0; 2001 char action; 2002 struct sctp_chunk *err_chk_p; 2003 2004 /* Make sure that the chunk has a valid length from the protocol 2005 * perspective. In this case check to make sure we have at least 2006 * enough for the chunk header. Cookie length verification is 2007 * done later. 2008 */ 2009 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2010 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2011 commands); 2012 2013 /* "Decode" the chunk. We have no optional parameters so we 2014 * are in good shape. 2015 */ 2016 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2017 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2018 sizeof(sctp_chunkhdr_t))) 2019 goto nomem; 2020 2021 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2022 * of a duplicate COOKIE ECHO match the Verification Tags of the 2023 * current association, consider the State Cookie valid even if 2024 * the lifespan is exceeded. 2025 */ 2026 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2027 &err_chk_p); 2028 2029 /* FIXME: 2030 * If the re-build failed, what is the proper error path 2031 * from here? 2032 * 2033 * [We should abort the association. --piggy] 2034 */ 2035 if (!new_asoc) { 2036 /* FIXME: Several errors are possible. A bad cookie should 2037 * be silently discarded, but think about logging it too. 2038 */ 2039 switch (error) { 2040 case -SCTP_IERROR_NOMEM: 2041 goto nomem; 2042 2043 case -SCTP_IERROR_STALE_COOKIE: 2044 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2045 err_chk_p); 2046 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2047 case -SCTP_IERROR_BAD_SIG: 2048 default: 2049 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2050 } 2051 } 2052 2053 /* Compare the tie_tag in cookie with the verification tag of 2054 * current association. 2055 */ 2056 action = sctp_tietags_compare(new_asoc, asoc); 2057 2058 switch (action) { 2059 case 'A': /* Association restart. */ 2060 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2061 new_asoc); 2062 break; 2063 2064 case 'B': /* Collision case B. */ 2065 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2066 new_asoc); 2067 break; 2068 2069 case 'C': /* Collision case C. */ 2070 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2071 new_asoc); 2072 break; 2073 2074 case 'D': /* Collision case D. */ 2075 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2076 new_asoc); 2077 break; 2078 2079 default: /* Discard packet for all others. */ 2080 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2081 break; 2082 } 2083 2084 /* Delete the tempory new association. */ 2085 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2086 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2087 2088 /* Restore association pointer to provide SCTP command interpeter 2089 * with a valid context in case it needs to manipulate 2090 * the queues */ 2091 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2092 SCTP_ASOC((struct sctp_association *)asoc)); 2093 2094 return retval; 2095 2096 nomem: 2097 return SCTP_DISPOSITION_NOMEM; 2098 } 2099 2100 /* 2101 * Process an ABORT. (SHUTDOWN-PENDING state) 2102 * 2103 * See sctp_sf_do_9_1_abort(). 2104 */ 2105 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2106 struct net *net, 2107 const struct sctp_endpoint *ep, 2108 const struct sctp_association *asoc, 2109 const sctp_subtype_t type, 2110 void *arg, 2111 sctp_cmd_seq_t *commands) 2112 { 2113 struct sctp_chunk *chunk = arg; 2114 2115 if (!sctp_vtag_verify_either(chunk, asoc)) 2116 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2117 2118 /* Make sure that the ABORT chunk has a valid length. 2119 * Since this is an ABORT chunk, we have to discard it 2120 * because of the following text: 2121 * RFC 2960, Section 3.3.7 2122 * If an endpoint receives an ABORT with a format error or for an 2123 * association that doesn't exist, it MUST silently discard it. 2124 * Because the length is "invalid", we can't really discard just 2125 * as we do not know its true length. So, to be safe, discard the 2126 * packet. 2127 */ 2128 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2129 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2130 2131 /* ADD-IP: Special case for ABORT chunks 2132 * F4) One special consideration is that ABORT Chunks arriving 2133 * destined to the IP address being deleted MUST be 2134 * ignored (see Section 5.3.1 for further details). 2135 */ 2136 if (SCTP_ADDR_DEL == 2137 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2138 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2139 2140 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2141 } 2142 2143 /* 2144 * Process an ABORT. (SHUTDOWN-SENT state) 2145 * 2146 * See sctp_sf_do_9_1_abort(). 2147 */ 2148 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2149 const struct sctp_endpoint *ep, 2150 const struct sctp_association *asoc, 2151 const sctp_subtype_t type, 2152 void *arg, 2153 sctp_cmd_seq_t *commands) 2154 { 2155 struct sctp_chunk *chunk = arg; 2156 2157 if (!sctp_vtag_verify_either(chunk, asoc)) 2158 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2159 2160 /* Make sure that the ABORT chunk has a valid length. 2161 * Since this is an ABORT chunk, we have to discard it 2162 * because of the following text: 2163 * RFC 2960, Section 3.3.7 2164 * If an endpoint receives an ABORT with a format error or for an 2165 * association that doesn't exist, it MUST silently discard it. 2166 * Because the length is "invalid", we can't really discard just 2167 * as we do not know its true length. So, to be safe, discard the 2168 * packet. 2169 */ 2170 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2172 2173 /* ADD-IP: Special case for ABORT chunks 2174 * F4) One special consideration is that ABORT Chunks arriving 2175 * destined to the IP address being deleted MUST be 2176 * ignored (see Section 5.3.1 for further details). 2177 */ 2178 if (SCTP_ADDR_DEL == 2179 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2180 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2181 2182 /* Stop the T2-shutdown timer. */ 2183 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2184 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2185 2186 /* Stop the T5-shutdown guard timer. */ 2187 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2188 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2189 2190 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2191 } 2192 2193 /* 2194 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2195 * 2196 * See sctp_sf_do_9_1_abort(). 2197 */ 2198 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2199 struct net *net, 2200 const struct sctp_endpoint *ep, 2201 const struct sctp_association *asoc, 2202 const sctp_subtype_t type, 2203 void *arg, 2204 sctp_cmd_seq_t *commands) 2205 { 2206 /* The same T2 timer, so we should be able to use 2207 * common function with the SHUTDOWN-SENT state. 2208 */ 2209 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2210 } 2211 2212 /* 2213 * Handle an Error received in COOKIE_ECHOED state. 2214 * 2215 * Only handle the error type of stale COOKIE Error, the other errors will 2216 * be ignored. 2217 * 2218 * Inputs 2219 * (endpoint, asoc, chunk) 2220 * 2221 * Outputs 2222 * (asoc, reply_msg, msg_up, timers, counters) 2223 * 2224 * The return value is the disposition of the chunk. 2225 */ 2226 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2227 const struct sctp_endpoint *ep, 2228 const struct sctp_association *asoc, 2229 const sctp_subtype_t type, 2230 void *arg, 2231 sctp_cmd_seq_t *commands) 2232 { 2233 struct sctp_chunk *chunk = arg; 2234 sctp_errhdr_t *err; 2235 2236 if (!sctp_vtag_verify(chunk, asoc)) 2237 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2238 2239 /* Make sure that the ERROR chunk has a valid length. 2240 * The parameter walking depends on this as well. 2241 */ 2242 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2243 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2244 commands); 2245 2246 /* Process the error here */ 2247 /* FUTURE FIXME: When PR-SCTP related and other optional 2248 * parms are emitted, this will have to change to handle multiple 2249 * errors. 2250 */ 2251 sctp_walk_errors(err, chunk->chunk_hdr) { 2252 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2253 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2254 arg, commands); 2255 } 2256 2257 /* It is possible to have malformed error causes, and that 2258 * will cause us to end the walk early. However, since 2259 * we are discarding the packet, there should be no adverse 2260 * affects. 2261 */ 2262 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2263 } 2264 2265 /* 2266 * Handle a Stale COOKIE Error 2267 * 2268 * Section: 5.2.6 Handle Stale COOKIE Error 2269 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2270 * one of the following three alternatives. 2271 * ... 2272 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2273 * Preservative parameter requesting an extension to the lifetime of 2274 * the State Cookie. When calculating the time extension, an 2275 * implementation SHOULD use the RTT information measured based on the 2276 * previous COOKIE ECHO / ERROR exchange, and should add no more 2277 * than 1 second beyond the measured RTT, due to long State Cookie 2278 * lifetimes making the endpoint more subject to a replay attack. 2279 * 2280 * Verification Tag: Not explicit, but safe to ignore. 2281 * 2282 * Inputs 2283 * (endpoint, asoc, chunk) 2284 * 2285 * Outputs 2286 * (asoc, reply_msg, msg_up, timers, counters) 2287 * 2288 * The return value is the disposition of the chunk. 2289 */ 2290 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2291 const struct sctp_endpoint *ep, 2292 const struct sctp_association *asoc, 2293 const sctp_subtype_t type, 2294 void *arg, 2295 sctp_cmd_seq_t *commands) 2296 { 2297 struct sctp_chunk *chunk = arg; 2298 time_t stale; 2299 sctp_cookie_preserve_param_t bht; 2300 sctp_errhdr_t *err; 2301 struct sctp_chunk *reply; 2302 struct sctp_bind_addr *bp; 2303 int attempts = asoc->init_err_counter + 1; 2304 2305 if (attempts > asoc->max_init_attempts) { 2306 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2307 SCTP_ERROR(ETIMEDOUT)); 2308 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2309 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2310 return SCTP_DISPOSITION_DELETE_TCB; 2311 } 2312 2313 err = (sctp_errhdr_t *)(chunk->skb->data); 2314 2315 /* When calculating the time extension, an implementation 2316 * SHOULD use the RTT information measured based on the 2317 * previous COOKIE ECHO / ERROR exchange, and should add no 2318 * more than 1 second beyond the measured RTT, due to long 2319 * State Cookie lifetimes making the endpoint more subject to 2320 * a replay attack. 2321 * Measure of Staleness's unit is usec. (1/1000000 sec) 2322 * Suggested Cookie Life-span Increment's unit is msec. 2323 * (1/1000 sec) 2324 * In general, if you use the suggested cookie life, the value 2325 * found in the field of measure of staleness should be doubled 2326 * to give ample time to retransmit the new cookie and thus 2327 * yield a higher probability of success on the reattempt. 2328 */ 2329 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2330 stale = (stale * 2) / 1000; 2331 2332 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2333 bht.param_hdr.length = htons(sizeof(bht)); 2334 bht.lifespan_increment = htonl(stale); 2335 2336 /* Build that new INIT chunk. */ 2337 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2338 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2339 if (!reply) 2340 goto nomem; 2341 2342 sctp_addto_chunk(reply, sizeof(bht), &bht); 2343 2344 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2345 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2346 2347 /* Stop pending T3-rtx and heartbeat timers */ 2348 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2349 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2350 2351 /* Delete non-primary peer ip addresses since we are transitioning 2352 * back to the COOKIE-WAIT state 2353 */ 2354 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2355 2356 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2357 * resend 2358 */ 2359 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2360 SCTP_TRANSPORT(asoc->peer.primary_path)); 2361 2362 /* Cast away the const modifier, as we want to just 2363 * rerun it through as a sideffect. 2364 */ 2365 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2366 2367 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2368 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2369 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2370 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2371 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2372 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2373 2374 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2375 2376 return SCTP_DISPOSITION_CONSUME; 2377 2378 nomem: 2379 return SCTP_DISPOSITION_NOMEM; 2380 } 2381 2382 /* 2383 * Process an ABORT. 2384 * 2385 * Section: 9.1 2386 * After checking the Verification Tag, the receiving endpoint shall 2387 * remove the association from its record, and shall report the 2388 * termination to its upper layer. 2389 * 2390 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2391 * B) Rules for packet carrying ABORT: 2392 * 2393 * - The endpoint shall always fill in the Verification Tag field of the 2394 * outbound packet with the destination endpoint's tag value if it 2395 * is known. 2396 * 2397 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2398 * MUST follow the procedure described in Section 8.4. 2399 * 2400 * - The receiver MUST accept the packet if the Verification Tag 2401 * matches either its own tag, OR the tag of its peer. Otherwise, the 2402 * receiver MUST silently discard the packet and take no further 2403 * action. 2404 * 2405 * Inputs 2406 * (endpoint, asoc, chunk) 2407 * 2408 * Outputs 2409 * (asoc, reply_msg, msg_up, timers, counters) 2410 * 2411 * The return value is the disposition of the chunk. 2412 */ 2413 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2414 const struct sctp_endpoint *ep, 2415 const struct sctp_association *asoc, 2416 const sctp_subtype_t type, 2417 void *arg, 2418 sctp_cmd_seq_t *commands) 2419 { 2420 struct sctp_chunk *chunk = arg; 2421 2422 if (!sctp_vtag_verify_either(chunk, asoc)) 2423 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2424 2425 /* Make sure that the ABORT chunk has a valid length. 2426 * Since this is an ABORT chunk, we have to discard it 2427 * because of the following text: 2428 * RFC 2960, Section 3.3.7 2429 * If an endpoint receives an ABORT with a format error or for an 2430 * association that doesn't exist, it MUST silently discard it. 2431 * Because the length is "invalid", we can't really discard just 2432 * as we do not know its true length. So, to be safe, discard the 2433 * packet. 2434 */ 2435 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2436 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2437 2438 /* ADD-IP: Special case for ABORT chunks 2439 * F4) One special consideration is that ABORT Chunks arriving 2440 * destined to the IP address being deleted MUST be 2441 * ignored (see Section 5.3.1 for further details). 2442 */ 2443 if (SCTP_ADDR_DEL == 2444 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2445 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2446 2447 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2448 } 2449 2450 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2451 const struct sctp_endpoint *ep, 2452 const struct sctp_association *asoc, 2453 const sctp_subtype_t type, 2454 void *arg, 2455 sctp_cmd_seq_t *commands) 2456 { 2457 struct sctp_chunk *chunk = arg; 2458 unsigned int len; 2459 __be16 error = SCTP_ERROR_NO_ERROR; 2460 2461 /* See if we have an error cause code in the chunk. */ 2462 len = ntohs(chunk->chunk_hdr->length); 2463 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2464 2465 sctp_errhdr_t *err; 2466 sctp_walk_errors(err, chunk->chunk_hdr); 2467 if ((void *)err != (void *)chunk->chunk_end) 2468 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2469 2470 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2471 } 2472 2473 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2474 /* ASSOC_FAILED will DELETE_TCB. */ 2475 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2476 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2477 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2478 2479 return SCTP_DISPOSITION_ABORT; 2480 } 2481 2482 /* 2483 * Process an ABORT. (COOKIE-WAIT state) 2484 * 2485 * See sctp_sf_do_9_1_abort() above. 2486 */ 2487 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2488 const struct sctp_endpoint *ep, 2489 const struct sctp_association *asoc, 2490 const sctp_subtype_t type, 2491 void *arg, 2492 sctp_cmd_seq_t *commands) 2493 { 2494 struct sctp_chunk *chunk = arg; 2495 unsigned int len; 2496 __be16 error = SCTP_ERROR_NO_ERROR; 2497 2498 if (!sctp_vtag_verify_either(chunk, asoc)) 2499 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2500 2501 /* Make sure that the ABORT chunk has a valid length. 2502 * Since this is an ABORT chunk, we have to discard it 2503 * because of the following text: 2504 * RFC 2960, Section 3.3.7 2505 * If an endpoint receives an ABORT with a format error or for an 2506 * association that doesn't exist, it MUST silently discard it. 2507 * Because the length is "invalid", we can't really discard just 2508 * as we do not know its true length. So, to be safe, discard the 2509 * packet. 2510 */ 2511 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2512 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2513 2514 /* See if we have an error cause code in the chunk. */ 2515 len = ntohs(chunk->chunk_hdr->length); 2516 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2517 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2518 2519 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2520 chunk->transport); 2521 } 2522 2523 /* 2524 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2525 */ 2526 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2527 const struct sctp_endpoint *ep, 2528 const struct sctp_association *asoc, 2529 const sctp_subtype_t type, 2530 void *arg, 2531 sctp_cmd_seq_t *commands) 2532 { 2533 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2534 ENOPROTOOPT, asoc, 2535 (struct sctp_transport *)arg); 2536 } 2537 2538 /* 2539 * Process an ABORT. (COOKIE-ECHOED state) 2540 */ 2541 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2542 const struct sctp_endpoint *ep, 2543 const struct sctp_association *asoc, 2544 const sctp_subtype_t type, 2545 void *arg, 2546 sctp_cmd_seq_t *commands) 2547 { 2548 /* There is a single T1 timer, so we should be able to use 2549 * common function with the COOKIE-WAIT state. 2550 */ 2551 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2552 } 2553 2554 /* 2555 * Stop T1 timer and abort association with "INIT failed". 2556 * 2557 * This is common code called by several sctp_sf_*_abort() functions above. 2558 */ 2559 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2560 sctp_cmd_seq_t *commands, 2561 __be16 error, int sk_err, 2562 const struct sctp_association *asoc, 2563 struct sctp_transport *transport) 2564 { 2565 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2566 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2567 SCTP_STATE(SCTP_STATE_CLOSED)); 2568 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2569 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2570 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2571 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2572 /* CMD_INIT_FAILED will DELETE_TCB. */ 2573 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2574 SCTP_PERR(error)); 2575 return SCTP_DISPOSITION_ABORT; 2576 } 2577 2578 /* 2579 * sctp_sf_do_9_2_shut 2580 * 2581 * Section: 9.2 2582 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2583 * - enter the SHUTDOWN-RECEIVED state, 2584 * 2585 * - stop accepting new data from its SCTP user 2586 * 2587 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2588 * that all its outstanding DATA chunks have been received by the 2589 * SHUTDOWN sender. 2590 * 2591 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2592 * send a SHUTDOWN in response to a ULP request. And should discard 2593 * subsequent SHUTDOWN chunks. 2594 * 2595 * If there are still outstanding DATA chunks left, the SHUTDOWN 2596 * receiver shall continue to follow normal data transmission 2597 * procedures defined in Section 6 until all outstanding DATA chunks 2598 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2599 * new data from its SCTP user. 2600 * 2601 * Verification Tag: 8.5 Verification Tag [Normal verification] 2602 * 2603 * Inputs 2604 * (endpoint, asoc, chunk) 2605 * 2606 * Outputs 2607 * (asoc, reply_msg, msg_up, timers, counters) 2608 * 2609 * The return value is the disposition of the chunk. 2610 */ 2611 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2612 const struct sctp_endpoint *ep, 2613 const struct sctp_association *asoc, 2614 const sctp_subtype_t type, 2615 void *arg, 2616 sctp_cmd_seq_t *commands) 2617 { 2618 struct sctp_chunk *chunk = arg; 2619 sctp_shutdownhdr_t *sdh; 2620 sctp_disposition_t disposition; 2621 struct sctp_ulpevent *ev; 2622 __u32 ctsn; 2623 2624 if (!sctp_vtag_verify(chunk, asoc)) 2625 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2626 2627 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2628 if (!sctp_chunk_length_valid(chunk, 2629 sizeof(struct sctp_shutdown_chunk_t))) 2630 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2631 commands); 2632 2633 /* Convert the elaborate header. */ 2634 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2635 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2636 chunk->subh.shutdown_hdr = sdh; 2637 ctsn = ntohl(sdh->cum_tsn_ack); 2638 2639 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2640 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2641 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2642 return SCTP_DISPOSITION_DISCARD; 2643 } 2644 2645 /* If Cumulative TSN Ack beyond the max tsn currently 2646 * send, terminating the association and respond to the 2647 * sender with an ABORT. 2648 */ 2649 if (!TSN_lt(ctsn, asoc->next_tsn)) 2650 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2651 2652 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2653 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2654 * inform the application that it should cease sending data. 2655 */ 2656 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2657 if (!ev) { 2658 disposition = SCTP_DISPOSITION_NOMEM; 2659 goto out; 2660 } 2661 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2662 2663 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2664 * - enter the SHUTDOWN-RECEIVED state, 2665 * - stop accepting new data from its SCTP user 2666 * 2667 * [This is implicit in the new state.] 2668 */ 2669 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2670 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2671 disposition = SCTP_DISPOSITION_CONSUME; 2672 2673 if (sctp_outq_is_empty(&asoc->outqueue)) { 2674 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2675 arg, commands); 2676 } 2677 2678 if (SCTP_DISPOSITION_NOMEM == disposition) 2679 goto out; 2680 2681 /* - verify, by checking the Cumulative TSN Ack field of the 2682 * chunk, that all its outstanding DATA chunks have been 2683 * received by the SHUTDOWN sender. 2684 */ 2685 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2686 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2687 2688 out: 2689 return disposition; 2690 } 2691 2692 /* 2693 * sctp_sf_do_9_2_shut_ctsn 2694 * 2695 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2696 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2697 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2698 * MUST be processed. 2699 */ 2700 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2701 const struct sctp_endpoint *ep, 2702 const struct sctp_association *asoc, 2703 const sctp_subtype_t type, 2704 void *arg, 2705 sctp_cmd_seq_t *commands) 2706 { 2707 struct sctp_chunk *chunk = arg; 2708 sctp_shutdownhdr_t *sdh; 2709 __u32 ctsn; 2710 2711 if (!sctp_vtag_verify(chunk, asoc)) 2712 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2713 2714 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2715 if (!sctp_chunk_length_valid(chunk, 2716 sizeof(struct sctp_shutdown_chunk_t))) 2717 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2718 commands); 2719 2720 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2721 ctsn = ntohl(sdh->cum_tsn_ack); 2722 2723 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2724 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2725 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2726 return SCTP_DISPOSITION_DISCARD; 2727 } 2728 2729 /* If Cumulative TSN Ack beyond the max tsn currently 2730 * send, terminating the association and respond to the 2731 * sender with an ABORT. 2732 */ 2733 if (!TSN_lt(ctsn, asoc->next_tsn)) 2734 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2735 2736 /* verify, by checking the Cumulative TSN Ack field of the 2737 * chunk, that all its outstanding DATA chunks have been 2738 * received by the SHUTDOWN sender. 2739 */ 2740 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2741 SCTP_BE32(sdh->cum_tsn_ack)); 2742 2743 return SCTP_DISPOSITION_CONSUME; 2744 } 2745 2746 /* RFC 2960 9.2 2747 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2748 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2749 * transport addresses (either in the IP addresses or in the INIT chunk) 2750 * that belong to this association, it should discard the INIT chunk and 2751 * retransmit the SHUTDOWN ACK chunk. 2752 */ 2753 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2754 const struct sctp_endpoint *ep, 2755 const struct sctp_association *asoc, 2756 const sctp_subtype_t type, 2757 void *arg, 2758 sctp_cmd_seq_t *commands) 2759 { 2760 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2761 struct sctp_chunk *reply; 2762 2763 /* Make sure that the chunk has a valid length */ 2764 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2765 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2766 commands); 2767 2768 /* Since we are not going to really process this INIT, there 2769 * is no point in verifying chunk boundries. Just generate 2770 * the SHUTDOWN ACK. 2771 */ 2772 reply = sctp_make_shutdown_ack(asoc, chunk); 2773 if (NULL == reply) 2774 goto nomem; 2775 2776 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2777 * the T2-SHUTDOWN timer. 2778 */ 2779 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2780 2781 /* and restart the T2-shutdown timer. */ 2782 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2783 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2784 2785 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2786 2787 return SCTP_DISPOSITION_CONSUME; 2788 nomem: 2789 return SCTP_DISPOSITION_NOMEM; 2790 } 2791 2792 /* 2793 * sctp_sf_do_ecn_cwr 2794 * 2795 * Section: Appendix A: Explicit Congestion Notification 2796 * 2797 * CWR: 2798 * 2799 * RFC 2481 details a specific bit for a sender to send in the header of 2800 * its next outbound TCP segment to indicate to its peer that it has 2801 * reduced its congestion window. This is termed the CWR bit. For 2802 * SCTP the same indication is made by including the CWR chunk. 2803 * This chunk contains one data element, i.e. the TSN number that 2804 * was sent in the ECNE chunk. This element represents the lowest 2805 * TSN number in the datagram that was originally marked with the 2806 * CE bit. 2807 * 2808 * Verification Tag: 8.5 Verification Tag [Normal verification] 2809 * Inputs 2810 * (endpoint, asoc, chunk) 2811 * 2812 * Outputs 2813 * (asoc, reply_msg, msg_up, timers, counters) 2814 * 2815 * The return value is the disposition of the chunk. 2816 */ 2817 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2818 const struct sctp_endpoint *ep, 2819 const struct sctp_association *asoc, 2820 const sctp_subtype_t type, 2821 void *arg, 2822 sctp_cmd_seq_t *commands) 2823 { 2824 sctp_cwrhdr_t *cwr; 2825 struct sctp_chunk *chunk = arg; 2826 u32 lowest_tsn; 2827 2828 if (!sctp_vtag_verify(chunk, asoc)) 2829 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2830 2831 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2832 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2833 commands); 2834 2835 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2836 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2837 2838 lowest_tsn = ntohl(cwr->lowest_tsn); 2839 2840 /* Does this CWR ack the last sent congestion notification? */ 2841 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2842 /* Stop sending ECNE. */ 2843 sctp_add_cmd_sf(commands, 2844 SCTP_CMD_ECN_CWR, 2845 SCTP_U32(lowest_tsn)); 2846 } 2847 return SCTP_DISPOSITION_CONSUME; 2848 } 2849 2850 /* 2851 * sctp_sf_do_ecne 2852 * 2853 * Section: Appendix A: Explicit Congestion Notification 2854 * 2855 * ECN-Echo 2856 * 2857 * RFC 2481 details a specific bit for a receiver to send back in its 2858 * TCP acknowledgements to notify the sender of the Congestion 2859 * Experienced (CE) bit having arrived from the network. For SCTP this 2860 * same indication is made by including the ECNE chunk. This chunk 2861 * contains one data element, i.e. the lowest TSN associated with the IP 2862 * datagram marked with the CE bit..... 2863 * 2864 * Verification Tag: 8.5 Verification Tag [Normal verification] 2865 * Inputs 2866 * (endpoint, asoc, chunk) 2867 * 2868 * Outputs 2869 * (asoc, reply_msg, msg_up, timers, counters) 2870 * 2871 * The return value is the disposition of the chunk. 2872 */ 2873 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2874 const struct sctp_endpoint *ep, 2875 const struct sctp_association *asoc, 2876 const sctp_subtype_t type, 2877 void *arg, 2878 sctp_cmd_seq_t *commands) 2879 { 2880 sctp_ecnehdr_t *ecne; 2881 struct sctp_chunk *chunk = arg; 2882 2883 if (!sctp_vtag_verify(chunk, asoc)) 2884 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2885 2886 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2887 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2888 commands); 2889 2890 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2891 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2892 2893 /* If this is a newer ECNE than the last CWR packet we sent out */ 2894 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2895 SCTP_U32(ntohl(ecne->lowest_tsn))); 2896 2897 return SCTP_DISPOSITION_CONSUME; 2898 } 2899 2900 /* 2901 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2902 * 2903 * The SCTP endpoint MUST always acknowledge the reception of each valid 2904 * DATA chunk. 2905 * 2906 * The guidelines on delayed acknowledgement algorithm specified in 2907 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2908 * acknowledgement SHOULD be generated for at least every second packet 2909 * (not every second DATA chunk) received, and SHOULD be generated within 2910 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2911 * situations it may be beneficial for an SCTP transmitter to be more 2912 * conservative than the algorithms detailed in this document allow. 2913 * However, an SCTP transmitter MUST NOT be more aggressive than the 2914 * following algorithms allow. 2915 * 2916 * A SCTP receiver MUST NOT generate more than one SACK for every 2917 * incoming packet, other than to update the offered window as the 2918 * receiving application consumes new data. 2919 * 2920 * Verification Tag: 8.5 Verification Tag [Normal verification] 2921 * 2922 * Inputs 2923 * (endpoint, asoc, chunk) 2924 * 2925 * Outputs 2926 * (asoc, reply_msg, msg_up, timers, counters) 2927 * 2928 * The return value is the disposition of the chunk. 2929 */ 2930 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2931 const struct sctp_endpoint *ep, 2932 const struct sctp_association *asoc, 2933 const sctp_subtype_t type, 2934 void *arg, 2935 sctp_cmd_seq_t *commands) 2936 { 2937 struct sctp_chunk *chunk = arg; 2938 sctp_arg_t force = SCTP_NOFORCE(); 2939 int error; 2940 2941 if (!sctp_vtag_verify(chunk, asoc)) { 2942 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2943 SCTP_NULL()); 2944 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2945 } 2946 2947 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2948 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2949 commands); 2950 2951 error = sctp_eat_data(asoc, chunk, commands ); 2952 switch (error) { 2953 case SCTP_IERROR_NO_ERROR: 2954 break; 2955 case SCTP_IERROR_HIGH_TSN: 2956 case SCTP_IERROR_BAD_STREAM: 2957 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2958 goto discard_noforce; 2959 case SCTP_IERROR_DUP_TSN: 2960 case SCTP_IERROR_IGNORE_TSN: 2961 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2962 goto discard_force; 2963 case SCTP_IERROR_NO_DATA: 2964 goto consume; 2965 case SCTP_IERROR_PROTO_VIOLATION: 2966 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2967 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2968 default: 2969 BUG(); 2970 } 2971 2972 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2973 force = SCTP_FORCE(); 2974 2975 if (asoc->autoclose) { 2976 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2977 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2978 } 2979 2980 /* If this is the last chunk in a packet, we need to count it 2981 * toward sack generation. Note that we need to SACK every 2982 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2983 * THEM. We elect to NOT generate SACK's if the chunk fails 2984 * the verification tag test. 2985 * 2986 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2987 * 2988 * The SCTP endpoint MUST always acknowledge the reception of 2989 * each valid DATA chunk. 2990 * 2991 * The guidelines on delayed acknowledgement algorithm 2992 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2993 * Specifically, an acknowledgement SHOULD be generated for at 2994 * least every second packet (not every second DATA chunk) 2995 * received, and SHOULD be generated within 200 ms of the 2996 * arrival of any unacknowledged DATA chunk. In some 2997 * situations it may be beneficial for an SCTP transmitter to 2998 * be more conservative than the algorithms detailed in this 2999 * document allow. However, an SCTP transmitter MUST NOT be 3000 * more aggressive than the following algorithms allow. 3001 */ 3002 if (chunk->end_of_packet) 3003 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3004 3005 return SCTP_DISPOSITION_CONSUME; 3006 3007 discard_force: 3008 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3009 * 3010 * When a packet arrives with duplicate DATA chunk(s) and with 3011 * no new DATA chunk(s), the endpoint MUST immediately send a 3012 * SACK with no delay. If a packet arrives with duplicate 3013 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3014 * MAY immediately send a SACK. Normally receipt of duplicate 3015 * DATA chunks will occur when the original SACK chunk was lost 3016 * and the peer's RTO has expired. The duplicate TSN number(s) 3017 * SHOULD be reported in the SACK as duplicate. 3018 */ 3019 /* In our case, we split the MAY SACK advice up whether or not 3020 * the last chunk is a duplicate.' 3021 */ 3022 if (chunk->end_of_packet) 3023 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3024 return SCTP_DISPOSITION_DISCARD; 3025 3026 discard_noforce: 3027 if (chunk->end_of_packet) 3028 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3029 3030 return SCTP_DISPOSITION_DISCARD; 3031 consume: 3032 return SCTP_DISPOSITION_CONSUME; 3033 3034 } 3035 3036 /* 3037 * sctp_sf_eat_data_fast_4_4 3038 * 3039 * Section: 4 (4) 3040 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3041 * DATA chunks without delay. 3042 * 3043 * Verification Tag: 8.5 Verification Tag [Normal verification] 3044 * Inputs 3045 * (endpoint, asoc, chunk) 3046 * 3047 * Outputs 3048 * (asoc, reply_msg, msg_up, timers, counters) 3049 * 3050 * The return value is the disposition of the chunk. 3051 */ 3052 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3053 const struct sctp_endpoint *ep, 3054 const struct sctp_association *asoc, 3055 const sctp_subtype_t type, 3056 void *arg, 3057 sctp_cmd_seq_t *commands) 3058 { 3059 struct sctp_chunk *chunk = arg; 3060 int error; 3061 3062 if (!sctp_vtag_verify(chunk, asoc)) { 3063 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3064 SCTP_NULL()); 3065 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3066 } 3067 3068 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3069 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3070 commands); 3071 3072 error = sctp_eat_data(asoc, chunk, commands ); 3073 switch (error) { 3074 case SCTP_IERROR_NO_ERROR: 3075 case SCTP_IERROR_HIGH_TSN: 3076 case SCTP_IERROR_DUP_TSN: 3077 case SCTP_IERROR_IGNORE_TSN: 3078 case SCTP_IERROR_BAD_STREAM: 3079 break; 3080 case SCTP_IERROR_NO_DATA: 3081 goto consume; 3082 case SCTP_IERROR_PROTO_VIOLATION: 3083 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3084 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3085 default: 3086 BUG(); 3087 } 3088 3089 /* Go a head and force a SACK, since we are shutting down. */ 3090 3091 /* Implementor's Guide. 3092 * 3093 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3094 * respond to each received packet containing one or more DATA chunk(s) 3095 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3096 */ 3097 if (chunk->end_of_packet) { 3098 /* We must delay the chunk creation since the cumulative 3099 * TSN has not been updated yet. 3100 */ 3101 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3102 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3103 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3104 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3105 } 3106 3107 consume: 3108 return SCTP_DISPOSITION_CONSUME; 3109 } 3110 3111 /* 3112 * Section: 6.2 Processing a Received SACK 3113 * D) Any time a SACK arrives, the endpoint performs the following: 3114 * 3115 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3116 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3117 * increasing, a SACK whose Cumulative TSN Ack is less than the 3118 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3119 * 3120 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3121 * of bytes still outstanding after processing the Cumulative TSN Ack 3122 * and the Gap Ack Blocks. 3123 * 3124 * iii) If the SACK is missing a TSN that was previously 3125 * acknowledged via a Gap Ack Block (e.g., the data receiver 3126 * reneged on the data), then mark the corresponding DATA chunk 3127 * as available for retransmit: Mark it as missing for fast 3128 * retransmit as described in Section 7.2.4 and if no retransmit 3129 * timer is running for the destination address to which the DATA 3130 * chunk was originally transmitted, then T3-rtx is started for 3131 * that destination address. 3132 * 3133 * Verification Tag: 8.5 Verification Tag [Normal verification] 3134 * 3135 * Inputs 3136 * (endpoint, asoc, chunk) 3137 * 3138 * Outputs 3139 * (asoc, reply_msg, msg_up, timers, counters) 3140 * 3141 * The return value is the disposition of the chunk. 3142 */ 3143 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3144 const struct sctp_endpoint *ep, 3145 const struct sctp_association *asoc, 3146 const sctp_subtype_t type, 3147 void *arg, 3148 sctp_cmd_seq_t *commands) 3149 { 3150 struct sctp_chunk *chunk = arg; 3151 sctp_sackhdr_t *sackh; 3152 __u32 ctsn; 3153 3154 if (!sctp_vtag_verify(chunk, asoc)) 3155 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3156 3157 /* Make sure that the SACK chunk has a valid length. */ 3158 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3159 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3160 commands); 3161 3162 /* Pull the SACK chunk from the data buffer */ 3163 sackh = sctp_sm_pull_sack(chunk); 3164 /* Was this a bogus SACK? */ 3165 if (!sackh) 3166 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3167 chunk->subh.sack_hdr = sackh; 3168 ctsn = ntohl(sackh->cum_tsn_ack); 3169 3170 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3171 * Ack Point, then drop the SACK. Since Cumulative TSN 3172 * Ack is monotonically increasing, a SACK whose 3173 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3174 * Point indicates an out-of-order SACK. 3175 */ 3176 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3177 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3178 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3179 return SCTP_DISPOSITION_DISCARD; 3180 } 3181 3182 /* If Cumulative TSN Ack beyond the max tsn currently 3183 * send, terminating the association and respond to the 3184 * sender with an ABORT. 3185 */ 3186 if (!TSN_lt(ctsn, asoc->next_tsn)) 3187 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3188 3189 /* Return this SACK for further processing. */ 3190 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3191 3192 /* Note: We do the rest of the work on the PROCESS_SACK 3193 * sideeffect. 3194 */ 3195 return SCTP_DISPOSITION_CONSUME; 3196 } 3197 3198 /* 3199 * Generate an ABORT in response to a packet. 3200 * 3201 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3202 * 3203 * 8) The receiver should respond to the sender of the OOTB packet with 3204 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3205 * MUST fill in the Verification Tag field of the outbound packet 3206 * with the value found in the Verification Tag field of the OOTB 3207 * packet and set the T-bit in the Chunk Flags to indicate that the 3208 * Verification Tag is reflected. After sending this ABORT, the 3209 * receiver of the OOTB packet shall discard the OOTB packet and take 3210 * no further action. 3211 * 3212 * Verification Tag: 3213 * 3214 * The return value is the disposition of the chunk. 3215 */ 3216 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3217 const struct sctp_endpoint *ep, 3218 const struct sctp_association *asoc, 3219 const sctp_subtype_t type, 3220 void *arg, 3221 sctp_cmd_seq_t *commands) 3222 { 3223 struct sctp_packet *packet = NULL; 3224 struct sctp_chunk *chunk = arg; 3225 struct sctp_chunk *abort; 3226 3227 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3228 3229 if (packet) { 3230 /* Make an ABORT. The T bit will be set if the asoc 3231 * is NULL. 3232 */ 3233 abort = sctp_make_abort(asoc, chunk, 0); 3234 if (!abort) { 3235 sctp_ootb_pkt_free(packet); 3236 return SCTP_DISPOSITION_NOMEM; 3237 } 3238 3239 /* Reflect vtag if T-Bit is set */ 3240 if (sctp_test_T_bit(abort)) 3241 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3242 3243 /* Set the skb to the belonging sock for accounting. */ 3244 abort->skb->sk = ep->base.sk; 3245 3246 sctp_packet_append_chunk(packet, abort); 3247 3248 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3249 SCTP_PACKET(packet)); 3250 3251 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3252 3253 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3254 return SCTP_DISPOSITION_CONSUME; 3255 } 3256 3257 return SCTP_DISPOSITION_NOMEM; 3258 } 3259 3260 /* 3261 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3262 * event as ULP notification for each cause included in the chunk. 3263 * 3264 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3265 * 3266 * The return value is the disposition of the chunk. 3267 */ 3268 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3269 const struct sctp_endpoint *ep, 3270 const struct sctp_association *asoc, 3271 const sctp_subtype_t type, 3272 void *arg, 3273 sctp_cmd_seq_t *commands) 3274 { 3275 struct sctp_chunk *chunk = arg; 3276 sctp_errhdr_t *err; 3277 3278 if (!sctp_vtag_verify(chunk, asoc)) 3279 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3280 3281 /* Make sure that the ERROR chunk has a valid length. */ 3282 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3283 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3284 commands); 3285 sctp_walk_errors(err, chunk->chunk_hdr); 3286 if ((void *)err != (void *)chunk->chunk_end) 3287 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3288 (void *)err, commands); 3289 3290 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3291 SCTP_CHUNK(chunk)); 3292 3293 return SCTP_DISPOSITION_CONSUME; 3294 } 3295 3296 /* 3297 * Process an inbound SHUTDOWN ACK. 3298 * 3299 * From Section 9.2: 3300 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3301 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3302 * peer, and remove all record of the association. 3303 * 3304 * The return value is the disposition. 3305 */ 3306 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3307 const struct sctp_endpoint *ep, 3308 const struct sctp_association *asoc, 3309 const sctp_subtype_t type, 3310 void *arg, 3311 sctp_cmd_seq_t *commands) 3312 { 3313 struct sctp_chunk *chunk = arg; 3314 struct sctp_chunk *reply; 3315 struct sctp_ulpevent *ev; 3316 3317 if (!sctp_vtag_verify(chunk, asoc)) 3318 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3319 3320 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3321 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3322 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3323 commands); 3324 /* 10.2 H) SHUTDOWN COMPLETE notification 3325 * 3326 * When SCTP completes the shutdown procedures (section 9.2) this 3327 * notification is passed to the upper layer. 3328 */ 3329 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3330 0, 0, 0, NULL, GFP_ATOMIC); 3331 if (!ev) 3332 goto nomem; 3333 3334 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3335 reply = sctp_make_shutdown_complete(asoc, chunk); 3336 if (!reply) 3337 goto nomem_chunk; 3338 3339 /* Do all the commands now (after allocation), so that we 3340 * have consistent state if memory allocation failes 3341 */ 3342 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3343 3344 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3345 * stop the T2-shutdown timer, 3346 */ 3347 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3348 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3349 3350 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3351 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3352 3353 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3354 SCTP_STATE(SCTP_STATE_CLOSED)); 3355 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3356 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3357 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3358 3359 /* ...and remove all record of the association. */ 3360 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3361 return SCTP_DISPOSITION_DELETE_TCB; 3362 3363 nomem_chunk: 3364 sctp_ulpevent_free(ev); 3365 nomem: 3366 return SCTP_DISPOSITION_NOMEM; 3367 } 3368 3369 /* 3370 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3371 * 3372 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3373 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3374 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3375 * packet must fill in the Verification Tag field of the outbound 3376 * packet with the Verification Tag received in the SHUTDOWN ACK and 3377 * set the T-bit in the Chunk Flags to indicate that the Verification 3378 * Tag is reflected. 3379 * 3380 * 8) The receiver should respond to the sender of the OOTB packet with 3381 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3382 * MUST fill in the Verification Tag field of the outbound packet 3383 * with the value found in the Verification Tag field of the OOTB 3384 * packet and set the T-bit in the Chunk Flags to indicate that the 3385 * Verification Tag is reflected. After sending this ABORT, the 3386 * receiver of the OOTB packet shall discard the OOTB packet and take 3387 * no further action. 3388 */ 3389 sctp_disposition_t sctp_sf_ootb(struct net *net, 3390 const struct sctp_endpoint *ep, 3391 const struct sctp_association *asoc, 3392 const sctp_subtype_t type, 3393 void *arg, 3394 sctp_cmd_seq_t *commands) 3395 { 3396 struct sctp_chunk *chunk = arg; 3397 struct sk_buff *skb = chunk->skb; 3398 sctp_chunkhdr_t *ch; 3399 sctp_errhdr_t *err; 3400 __u8 *ch_end; 3401 int ootb_shut_ack = 0; 3402 int ootb_cookie_ack = 0; 3403 3404 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3405 3406 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3407 do { 3408 /* Report violation if the chunk is less then minimal */ 3409 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3410 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3411 commands); 3412 3413 /* Now that we know we at least have a chunk header, 3414 * do things that are type appropriate. 3415 */ 3416 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3417 ootb_shut_ack = 1; 3418 3419 /* RFC 2960, Section 3.3.7 3420 * Moreover, under any circumstances, an endpoint that 3421 * receives an ABORT MUST NOT respond to that ABORT by 3422 * sending an ABORT of its own. 3423 */ 3424 if (SCTP_CID_ABORT == ch->type) 3425 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3426 3427 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3428 * or a COOKIE ACK the SCTP Packet should be silently 3429 * discarded. 3430 */ 3431 3432 if (SCTP_CID_COOKIE_ACK == ch->type) 3433 ootb_cookie_ack = 1; 3434 3435 if (SCTP_CID_ERROR == ch->type) { 3436 sctp_walk_errors(err, ch) { 3437 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3438 ootb_cookie_ack = 1; 3439 break; 3440 } 3441 } 3442 } 3443 3444 /* Report violation if chunk len overflows */ 3445 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3446 if (ch_end > skb_tail_pointer(skb)) 3447 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3448 commands); 3449 3450 ch = (sctp_chunkhdr_t *) ch_end; 3451 } while (ch_end < skb_tail_pointer(skb)); 3452 3453 if (ootb_shut_ack) 3454 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3455 else if (ootb_cookie_ack) 3456 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3457 else 3458 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3459 } 3460 3461 /* 3462 * Handle an "Out of the blue" SHUTDOWN ACK. 3463 * 3464 * Section: 8.4 5, sctpimpguide 2.41. 3465 * 3466 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3467 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3468 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3469 * packet must fill in the Verification Tag field of the outbound 3470 * packet with the Verification Tag received in the SHUTDOWN ACK and 3471 * set the T-bit in the Chunk Flags to indicate that the Verification 3472 * Tag is reflected. 3473 * 3474 * Inputs 3475 * (endpoint, asoc, type, arg, commands) 3476 * 3477 * Outputs 3478 * (sctp_disposition_t) 3479 * 3480 * The return value is the disposition of the chunk. 3481 */ 3482 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3483 const struct sctp_endpoint *ep, 3484 const struct sctp_association *asoc, 3485 const sctp_subtype_t type, 3486 void *arg, 3487 sctp_cmd_seq_t *commands) 3488 { 3489 struct sctp_packet *packet = NULL; 3490 struct sctp_chunk *chunk = arg; 3491 struct sctp_chunk *shut; 3492 3493 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3494 3495 if (packet) { 3496 /* Make an SHUTDOWN_COMPLETE. 3497 * The T bit will be set if the asoc is NULL. 3498 */ 3499 shut = sctp_make_shutdown_complete(asoc, chunk); 3500 if (!shut) { 3501 sctp_ootb_pkt_free(packet); 3502 return SCTP_DISPOSITION_NOMEM; 3503 } 3504 3505 /* Reflect vtag if T-Bit is set */ 3506 if (sctp_test_T_bit(shut)) 3507 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3508 3509 /* Set the skb to the belonging sock for accounting. */ 3510 shut->skb->sk = ep->base.sk; 3511 3512 sctp_packet_append_chunk(packet, shut); 3513 3514 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3515 SCTP_PACKET(packet)); 3516 3517 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3518 3519 /* If the chunk length is invalid, we don't want to process 3520 * the reset of the packet. 3521 */ 3522 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3524 3525 /* We need to discard the rest of the packet to prevent 3526 * potential bomming attacks from additional bundled chunks. 3527 * This is documented in SCTP Threats ID. 3528 */ 3529 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3530 } 3531 3532 return SCTP_DISPOSITION_NOMEM; 3533 } 3534 3535 /* 3536 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3537 * 3538 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3539 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3540 * procedures in section 8.4 SHOULD be followed, in other words it 3541 * should be treated as an Out Of The Blue packet. 3542 * [This means that we do NOT check the Verification Tag on these 3543 * chunks. --piggy ] 3544 * 3545 */ 3546 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3547 const struct sctp_endpoint *ep, 3548 const struct sctp_association *asoc, 3549 const sctp_subtype_t type, 3550 void *arg, 3551 sctp_cmd_seq_t *commands) 3552 { 3553 struct sctp_chunk *chunk = arg; 3554 3555 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3556 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3557 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3558 commands); 3559 3560 /* Although we do have an association in this case, it corresponds 3561 * to a restarted association. So the packet is treated as an OOTB 3562 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3563 * called with a NULL association. 3564 */ 3565 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3566 3567 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3568 } 3569 3570 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3571 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3572 const struct sctp_endpoint *ep, 3573 const struct sctp_association *asoc, 3574 const sctp_subtype_t type, void *arg, 3575 sctp_cmd_seq_t *commands) 3576 { 3577 struct sctp_chunk *chunk = arg; 3578 struct sctp_chunk *asconf_ack = NULL; 3579 struct sctp_paramhdr *err_param = NULL; 3580 sctp_addiphdr_t *hdr; 3581 union sctp_addr_param *addr_param; 3582 __u32 serial; 3583 int length; 3584 3585 if (!sctp_vtag_verify(chunk, asoc)) { 3586 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3587 SCTP_NULL()); 3588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3589 } 3590 3591 /* ADD-IP: Section 4.1.1 3592 * This chunk MUST be sent in an authenticated way by using 3593 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3594 * is received unauthenticated it MUST be silently discarded as 3595 * described in [I-D.ietf-tsvwg-sctp-auth]. 3596 */ 3597 if (!net->sctp.addip_noauth && !chunk->auth) 3598 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3599 3600 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3601 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3602 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3603 commands); 3604 3605 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3606 serial = ntohl(hdr->serial); 3607 3608 addr_param = (union sctp_addr_param *)hdr->params; 3609 length = ntohs(addr_param->p.length); 3610 if (length < sizeof(sctp_paramhdr_t)) 3611 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3612 (void *)addr_param, commands); 3613 3614 /* Verify the ASCONF chunk before processing it. */ 3615 if (!sctp_verify_asconf(asoc, 3616 (sctp_paramhdr_t *)((void *)addr_param + length), 3617 (void *)chunk->chunk_end, 3618 &err_param)) 3619 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3620 (void *)err_param, commands); 3621 3622 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3623 * the endpoint stored in a new association variable 3624 * 'Peer-Serial-Number'. 3625 */ 3626 if (serial == asoc->peer.addip_serial + 1) { 3627 /* If this is the first instance of ASCONF in the packet, 3628 * we can clean our old ASCONF-ACKs. 3629 */ 3630 if (!chunk->has_asconf) 3631 sctp_assoc_clean_asconf_ack_cache(asoc); 3632 3633 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3634 * expected, process the ASCONF as described below and after 3635 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3636 * the response packet and cache a copy of it (in the event it 3637 * later needs to be retransmitted). 3638 * 3639 * Essentially, do V1-V5. 3640 */ 3641 asconf_ack = sctp_process_asconf((struct sctp_association *) 3642 asoc, chunk); 3643 if (!asconf_ack) 3644 return SCTP_DISPOSITION_NOMEM; 3645 } else if (serial < asoc->peer.addip_serial + 1) { 3646 /* ADDIP 5.2 E2) 3647 * If the value found in the Sequence Number is less than the 3648 * ('Peer- Sequence-Number' + 1), simply skip to the next 3649 * ASCONF, and include in the outbound response packet 3650 * any previously cached ASCONF-ACK response that was 3651 * sent and saved that matches the Sequence Number of the 3652 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3653 * Chunk exists. This will occur when an older ASCONF 3654 * arrives out of order. In such a case, the receiver 3655 * should skip the ASCONF Chunk and not include ASCONF-ACK 3656 * Chunk for that chunk. 3657 */ 3658 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3659 if (!asconf_ack) 3660 return SCTP_DISPOSITION_DISCARD; 3661 3662 /* Reset the transport so that we select the correct one 3663 * this time around. This is to make sure that we don't 3664 * accidentally use a stale transport that's been removed. 3665 */ 3666 asconf_ack->transport = NULL; 3667 } else { 3668 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3669 * it must be either a stale packet or from an attacker. 3670 */ 3671 return SCTP_DISPOSITION_DISCARD; 3672 } 3673 3674 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3675 * containing the ASCONF-ACK Chunks MUST be the source address of 3676 * the SCTP packet that held the ASCONF Chunks. 3677 * 3678 * To do this properly, we'll set the destination address of the chunk 3679 * and at the transmit time, will try look up the transport to use. 3680 * Since ASCONFs may be bundled, the correct transport may not be 3681 * created until we process the entire packet, thus this workaround. 3682 */ 3683 asconf_ack->dest = chunk->source; 3684 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3685 if (asoc->new_transport) { 3686 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, 3687 commands); 3688 ((struct sctp_association *)asoc)->new_transport = NULL; 3689 } 3690 3691 return SCTP_DISPOSITION_CONSUME; 3692 } 3693 3694 /* 3695 * ADDIP Section 4.3 General rules for address manipulation 3696 * When building TLV parameters for the ASCONF Chunk that will add or 3697 * delete IP addresses the D0 to D13 rules should be applied: 3698 */ 3699 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3700 const struct sctp_endpoint *ep, 3701 const struct sctp_association *asoc, 3702 const sctp_subtype_t type, void *arg, 3703 sctp_cmd_seq_t *commands) 3704 { 3705 struct sctp_chunk *asconf_ack = arg; 3706 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3707 struct sctp_chunk *abort; 3708 struct sctp_paramhdr *err_param = NULL; 3709 sctp_addiphdr_t *addip_hdr; 3710 __u32 sent_serial, rcvd_serial; 3711 3712 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3713 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3714 SCTP_NULL()); 3715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3716 } 3717 3718 /* ADD-IP, Section 4.1.2: 3719 * This chunk MUST be sent in an authenticated way by using 3720 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3721 * is received unauthenticated it MUST be silently discarded as 3722 * described in [I-D.ietf-tsvwg-sctp-auth]. 3723 */ 3724 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3725 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3726 3727 /* Make sure that the ADDIP chunk has a valid length. */ 3728 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3729 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3730 commands); 3731 3732 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3733 rcvd_serial = ntohl(addip_hdr->serial); 3734 3735 /* Verify the ASCONF-ACK chunk before processing it. */ 3736 if (!sctp_verify_asconf(asoc, 3737 (sctp_paramhdr_t *)addip_hdr->params, 3738 (void *)asconf_ack->chunk_end, 3739 &err_param)) 3740 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3741 (void *)err_param, commands); 3742 3743 if (last_asconf) { 3744 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3745 sent_serial = ntohl(addip_hdr->serial); 3746 } else { 3747 sent_serial = asoc->addip_serial - 1; 3748 } 3749 3750 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3751 * equal to the next serial number to be used but no ASCONF chunk is 3752 * outstanding the endpoint MUST ABORT the association. Note that a 3753 * sequence number is greater than if it is no more than 2^^31-1 3754 * larger than the current sequence number (using serial arithmetic). 3755 */ 3756 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3757 !(asoc->addip_last_asconf)) { 3758 abort = sctp_make_abort(asoc, asconf_ack, 3759 sizeof(sctp_errhdr_t)); 3760 if (abort) { 3761 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3762 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3763 SCTP_CHUNK(abort)); 3764 } 3765 /* We are going to ABORT, so we might as well stop 3766 * processing the rest of the chunks in the packet. 3767 */ 3768 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3769 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3770 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3771 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3772 SCTP_ERROR(ECONNABORTED)); 3773 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3774 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3775 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3776 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3777 return SCTP_DISPOSITION_ABORT; 3778 } 3779 3780 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3781 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3782 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3783 3784 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3785 asconf_ack)) { 3786 /* Successfully processed ASCONF_ACK. We can 3787 * release the next asconf if we have one. 3788 */ 3789 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3790 SCTP_NULL()); 3791 return SCTP_DISPOSITION_CONSUME; 3792 } 3793 3794 abort = sctp_make_abort(asoc, asconf_ack, 3795 sizeof(sctp_errhdr_t)); 3796 if (abort) { 3797 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3798 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3799 SCTP_CHUNK(abort)); 3800 } 3801 /* We are going to ABORT, so we might as well stop 3802 * processing the rest of the chunks in the packet. 3803 */ 3804 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3805 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3806 SCTP_ERROR(ECONNABORTED)); 3807 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3808 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3809 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3810 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3811 return SCTP_DISPOSITION_ABORT; 3812 } 3813 3814 return SCTP_DISPOSITION_DISCARD; 3815 } 3816 3817 /* 3818 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3819 * 3820 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3821 * its cumulative TSN point to the value carried in the FORWARD TSN 3822 * chunk, and then MUST further advance its cumulative TSN point locally 3823 * if possible. 3824 * After the above processing, the data receiver MUST stop reporting any 3825 * missing TSNs earlier than or equal to the new cumulative TSN point. 3826 * 3827 * Verification Tag: 8.5 Verification Tag [Normal verification] 3828 * 3829 * The return value is the disposition of the chunk. 3830 */ 3831 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3832 const struct sctp_endpoint *ep, 3833 const struct sctp_association *asoc, 3834 const sctp_subtype_t type, 3835 void *arg, 3836 sctp_cmd_seq_t *commands) 3837 { 3838 struct sctp_chunk *chunk = arg; 3839 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3840 struct sctp_fwdtsn_skip *skip; 3841 __u16 len; 3842 __u32 tsn; 3843 3844 if (!sctp_vtag_verify(chunk, asoc)) { 3845 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3846 SCTP_NULL()); 3847 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3848 } 3849 3850 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3851 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3852 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3853 commands); 3854 3855 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3856 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3857 len = ntohs(chunk->chunk_hdr->length); 3858 len -= sizeof(struct sctp_chunkhdr); 3859 skb_pull(chunk->skb, len); 3860 3861 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3862 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3863 3864 /* The TSN is too high--silently discard the chunk and count on it 3865 * getting retransmitted later. 3866 */ 3867 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3868 goto discard_noforce; 3869 3870 /* Silently discard the chunk if stream-id is not valid */ 3871 sctp_walk_fwdtsn(skip, chunk) { 3872 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3873 goto discard_noforce; 3874 } 3875 3876 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3877 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3878 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3879 SCTP_CHUNK(chunk)); 3880 3881 /* Count this as receiving DATA. */ 3882 if (asoc->autoclose) { 3883 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3884 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3885 } 3886 3887 /* FIXME: For now send a SACK, but DATA processing may 3888 * send another. 3889 */ 3890 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3891 3892 return SCTP_DISPOSITION_CONSUME; 3893 3894 discard_noforce: 3895 return SCTP_DISPOSITION_DISCARD; 3896 } 3897 3898 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3899 struct net *net, 3900 const struct sctp_endpoint *ep, 3901 const struct sctp_association *asoc, 3902 const sctp_subtype_t type, 3903 void *arg, 3904 sctp_cmd_seq_t *commands) 3905 { 3906 struct sctp_chunk *chunk = arg; 3907 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3908 struct sctp_fwdtsn_skip *skip; 3909 __u16 len; 3910 __u32 tsn; 3911 3912 if (!sctp_vtag_verify(chunk, asoc)) { 3913 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3914 SCTP_NULL()); 3915 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3916 } 3917 3918 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3919 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3920 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3921 commands); 3922 3923 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3924 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3925 len = ntohs(chunk->chunk_hdr->length); 3926 len -= sizeof(struct sctp_chunkhdr); 3927 skb_pull(chunk->skb, len); 3928 3929 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3930 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3931 3932 /* The TSN is too high--silently discard the chunk and count on it 3933 * getting retransmitted later. 3934 */ 3935 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3936 goto gen_shutdown; 3937 3938 /* Silently discard the chunk if stream-id is not valid */ 3939 sctp_walk_fwdtsn(skip, chunk) { 3940 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3941 goto gen_shutdown; 3942 } 3943 3944 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3945 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3946 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3947 SCTP_CHUNK(chunk)); 3948 3949 /* Go a head and force a SACK, since we are shutting down. */ 3950 gen_shutdown: 3951 /* Implementor's Guide. 3952 * 3953 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3954 * respond to each received packet containing one or more DATA chunk(s) 3955 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3956 */ 3957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3958 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3960 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3961 3962 return SCTP_DISPOSITION_CONSUME; 3963 } 3964 3965 /* 3966 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3967 * 3968 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3969 * Identifier field. If this algorithm was not specified by the 3970 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3971 * during association setup, the AUTH chunk and all chunks after it MUST 3972 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3973 * defined in Section 4.1. 3974 * 3975 * If an endpoint with no shared key receives a Shared Key Identifier 3976 * other than 0, it MUST silently discard all authenticated chunks. If 3977 * the endpoint has at least one endpoint pair shared key for the peer, 3978 * it MUST use the key specified by the Shared Key Identifier if a 3979 * key has been configured for that Shared Key Identifier. If no 3980 * endpoint pair shared key has been configured for that Shared Key 3981 * Identifier, all authenticated chunks MUST be silently discarded. 3982 * 3983 * Verification Tag: 8.5 Verification Tag [Normal verification] 3984 * 3985 * The return value is the disposition of the chunk. 3986 */ 3987 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3988 const struct sctp_endpoint *ep, 3989 const struct sctp_association *asoc, 3990 const sctp_subtype_t type, 3991 struct sctp_chunk *chunk) 3992 { 3993 struct sctp_authhdr *auth_hdr; 3994 struct sctp_hmac *hmac; 3995 unsigned int sig_len; 3996 __u16 key_id; 3997 __u8 *save_digest; 3998 __u8 *digest; 3999 4000 /* Pull in the auth header, so we can do some more verification */ 4001 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4002 chunk->subh.auth_hdr = auth_hdr; 4003 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4004 4005 /* Make sure that we support the HMAC algorithm from the auth 4006 * chunk. 4007 */ 4008 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4009 return SCTP_IERROR_AUTH_BAD_HMAC; 4010 4011 /* Make sure that the provided shared key identifier has been 4012 * configured 4013 */ 4014 key_id = ntohs(auth_hdr->shkey_id); 4015 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4016 return SCTP_IERROR_AUTH_BAD_KEYID; 4017 4018 4019 /* Make sure that the length of the signature matches what 4020 * we expect. 4021 */ 4022 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4023 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4024 if (sig_len != hmac->hmac_len) 4025 return SCTP_IERROR_PROTO_VIOLATION; 4026 4027 /* Now that we've done validation checks, we can compute and 4028 * verify the hmac. The steps involved are: 4029 * 1. Save the digest from the chunk. 4030 * 2. Zero out the digest in the chunk. 4031 * 3. Compute the new digest 4032 * 4. Compare saved and new digests. 4033 */ 4034 digest = auth_hdr->hmac; 4035 skb_pull(chunk->skb, sig_len); 4036 4037 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4038 if (!save_digest) 4039 goto nomem; 4040 4041 memset(digest, 0, sig_len); 4042 4043 sctp_auth_calculate_hmac(asoc, chunk->skb, 4044 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4045 GFP_ATOMIC); 4046 4047 /* Discard the packet if the digests do not match */ 4048 if (memcmp(save_digest, digest, sig_len)) { 4049 kfree(save_digest); 4050 return SCTP_IERROR_BAD_SIG; 4051 } 4052 4053 kfree(save_digest); 4054 chunk->auth = 1; 4055 4056 return SCTP_IERROR_NO_ERROR; 4057 nomem: 4058 return SCTP_IERROR_NOMEM; 4059 } 4060 4061 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4062 const struct sctp_endpoint *ep, 4063 const struct sctp_association *asoc, 4064 const sctp_subtype_t type, 4065 void *arg, 4066 sctp_cmd_seq_t *commands) 4067 { 4068 struct sctp_authhdr *auth_hdr; 4069 struct sctp_chunk *chunk = arg; 4070 struct sctp_chunk *err_chunk; 4071 sctp_ierror_t error; 4072 4073 /* Make sure that the peer has AUTH capable */ 4074 if (!asoc->peer.auth_capable) 4075 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4076 4077 if (!sctp_vtag_verify(chunk, asoc)) { 4078 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4079 SCTP_NULL()); 4080 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4081 } 4082 4083 /* Make sure that the AUTH chunk has valid length. */ 4084 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4085 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4086 commands); 4087 4088 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4089 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4090 switch (error) { 4091 case SCTP_IERROR_AUTH_BAD_HMAC: 4092 /* Generate the ERROR chunk and discard the rest 4093 * of the packet 4094 */ 4095 err_chunk = sctp_make_op_error(asoc, chunk, 4096 SCTP_ERROR_UNSUP_HMAC, 4097 &auth_hdr->hmac_id, 4098 sizeof(__u16), 0); 4099 if (err_chunk) { 4100 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4101 SCTP_CHUNK(err_chunk)); 4102 } 4103 /* Fall Through */ 4104 case SCTP_IERROR_AUTH_BAD_KEYID: 4105 case SCTP_IERROR_BAD_SIG: 4106 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4107 4108 case SCTP_IERROR_PROTO_VIOLATION: 4109 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4110 commands); 4111 4112 case SCTP_IERROR_NOMEM: 4113 return SCTP_DISPOSITION_NOMEM; 4114 4115 default: /* Prevent gcc warnings */ 4116 break; 4117 } 4118 4119 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4120 struct sctp_ulpevent *ev; 4121 4122 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4123 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4124 4125 if (!ev) 4126 return -ENOMEM; 4127 4128 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4129 SCTP_ULPEVENT(ev)); 4130 } 4131 4132 return SCTP_DISPOSITION_CONSUME; 4133 } 4134 4135 /* 4136 * Process an unknown chunk. 4137 * 4138 * Section: 3.2. Also, 2.1 in the implementor's guide. 4139 * 4140 * Chunk Types are encoded such that the highest-order two bits specify 4141 * the action that must be taken if the processing endpoint does not 4142 * recognize the Chunk Type. 4143 * 4144 * 00 - Stop processing this SCTP packet and discard it, do not process 4145 * any further chunks within it. 4146 * 4147 * 01 - Stop processing this SCTP packet and discard it, do not process 4148 * any further chunks within it, and report the unrecognized 4149 * chunk in an 'Unrecognized Chunk Type'. 4150 * 4151 * 10 - Skip this chunk and continue processing. 4152 * 4153 * 11 - Skip this chunk and continue processing, but report in an ERROR 4154 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4155 * 4156 * The return value is the disposition of the chunk. 4157 */ 4158 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4159 const struct sctp_endpoint *ep, 4160 const struct sctp_association *asoc, 4161 const sctp_subtype_t type, 4162 void *arg, 4163 sctp_cmd_seq_t *commands) 4164 { 4165 struct sctp_chunk *unk_chunk = arg; 4166 struct sctp_chunk *err_chunk; 4167 sctp_chunkhdr_t *hdr; 4168 4169 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 4170 4171 if (!sctp_vtag_verify(unk_chunk, asoc)) 4172 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4173 4174 /* Make sure that the chunk has a valid length. 4175 * Since we don't know the chunk type, we use a general 4176 * chunkhdr structure to make a comparison. 4177 */ 4178 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4179 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4180 commands); 4181 4182 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4183 case SCTP_CID_ACTION_DISCARD: 4184 /* Discard the packet. */ 4185 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4186 break; 4187 case SCTP_CID_ACTION_DISCARD_ERR: 4188 /* Generate an ERROR chunk as response. */ 4189 hdr = unk_chunk->chunk_hdr; 4190 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4191 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4192 WORD_ROUND(ntohs(hdr->length)), 4193 0); 4194 if (err_chunk) { 4195 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4196 SCTP_CHUNK(err_chunk)); 4197 } 4198 4199 /* Discard the packet. */ 4200 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4201 return SCTP_DISPOSITION_CONSUME; 4202 break; 4203 case SCTP_CID_ACTION_SKIP: 4204 /* Skip the chunk. */ 4205 return SCTP_DISPOSITION_DISCARD; 4206 break; 4207 case SCTP_CID_ACTION_SKIP_ERR: 4208 /* Generate an ERROR chunk as response. */ 4209 hdr = unk_chunk->chunk_hdr; 4210 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4211 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4212 WORD_ROUND(ntohs(hdr->length)), 4213 0); 4214 if (err_chunk) { 4215 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4216 SCTP_CHUNK(err_chunk)); 4217 } 4218 /* Skip the chunk. */ 4219 return SCTP_DISPOSITION_CONSUME; 4220 break; 4221 default: 4222 break; 4223 } 4224 4225 return SCTP_DISPOSITION_DISCARD; 4226 } 4227 4228 /* 4229 * Discard the chunk. 4230 * 4231 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4232 * [Too numerous to mention...] 4233 * Verification Tag: No verification needed. 4234 * Inputs 4235 * (endpoint, asoc, chunk) 4236 * 4237 * Outputs 4238 * (asoc, reply_msg, msg_up, timers, counters) 4239 * 4240 * The return value is the disposition of the chunk. 4241 */ 4242 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4243 const struct sctp_endpoint *ep, 4244 const struct sctp_association *asoc, 4245 const sctp_subtype_t type, 4246 void *arg, 4247 sctp_cmd_seq_t *commands) 4248 { 4249 struct sctp_chunk *chunk = arg; 4250 4251 /* Make sure that the chunk has a valid length. 4252 * Since we don't know the chunk type, we use a general 4253 * chunkhdr structure to make a comparison. 4254 */ 4255 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4256 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4257 commands); 4258 4259 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4260 return SCTP_DISPOSITION_DISCARD; 4261 } 4262 4263 /* 4264 * Discard the whole packet. 4265 * 4266 * Section: 8.4 2) 4267 * 4268 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4269 * silently discard the OOTB packet and take no further action. 4270 * 4271 * Verification Tag: No verification necessary 4272 * 4273 * Inputs 4274 * (endpoint, asoc, chunk) 4275 * 4276 * Outputs 4277 * (asoc, reply_msg, msg_up, timers, counters) 4278 * 4279 * The return value is the disposition of the chunk. 4280 */ 4281 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4282 const struct sctp_endpoint *ep, 4283 const struct sctp_association *asoc, 4284 const sctp_subtype_t type, 4285 void *arg, 4286 sctp_cmd_seq_t *commands) 4287 { 4288 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4289 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4290 4291 return SCTP_DISPOSITION_CONSUME; 4292 } 4293 4294 4295 /* 4296 * The other end is violating protocol. 4297 * 4298 * Section: Not specified 4299 * Verification Tag: Not specified 4300 * Inputs 4301 * (endpoint, asoc, chunk) 4302 * 4303 * Outputs 4304 * (asoc, reply_msg, msg_up, timers, counters) 4305 * 4306 * We simply tag the chunk as a violation. The state machine will log 4307 * the violation and continue. 4308 */ 4309 sctp_disposition_t sctp_sf_violation(struct net *net, 4310 const struct sctp_endpoint *ep, 4311 const struct sctp_association *asoc, 4312 const sctp_subtype_t type, 4313 void *arg, 4314 sctp_cmd_seq_t *commands) 4315 { 4316 struct sctp_chunk *chunk = arg; 4317 4318 /* Make sure that the chunk has a valid length. */ 4319 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4320 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4321 commands); 4322 4323 return SCTP_DISPOSITION_VIOLATION; 4324 } 4325 4326 /* 4327 * Common function to handle a protocol violation. 4328 */ 4329 static sctp_disposition_t sctp_sf_abort_violation( 4330 struct net *net, 4331 const struct sctp_endpoint *ep, 4332 const struct sctp_association *asoc, 4333 void *arg, 4334 sctp_cmd_seq_t *commands, 4335 const __u8 *payload, 4336 const size_t paylen) 4337 { 4338 struct sctp_packet *packet = NULL; 4339 struct sctp_chunk *chunk = arg; 4340 struct sctp_chunk *abort = NULL; 4341 4342 /* SCTP-AUTH, Section 6.3: 4343 * It should be noted that if the receiver wants to tear 4344 * down an association in an authenticated way only, the 4345 * handling of malformed packets should not result in 4346 * tearing down the association. 4347 * 4348 * This means that if we only want to abort associations 4349 * in an authenticated way (i.e AUTH+ABORT), then we 4350 * can't destroy this association just because the packet 4351 * was malformed. 4352 */ 4353 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4354 goto discard; 4355 4356 /* Make the abort chunk. */ 4357 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4358 if (!abort) 4359 goto nomem; 4360 4361 if (asoc) { 4362 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4363 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4364 !asoc->peer.i.init_tag) { 4365 sctp_initack_chunk_t *initack; 4366 4367 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4368 if (!sctp_chunk_length_valid(chunk, 4369 sizeof(sctp_initack_chunk_t))) 4370 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4371 else { 4372 unsigned int inittag; 4373 4374 inittag = ntohl(initack->init_hdr.init_tag); 4375 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4376 SCTP_U32(inittag)); 4377 } 4378 } 4379 4380 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4381 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4382 4383 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4384 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4385 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4386 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4387 SCTP_ERROR(ECONNREFUSED)); 4388 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4389 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4390 } else { 4391 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4392 SCTP_ERROR(ECONNABORTED)); 4393 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4394 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4395 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4396 } 4397 } else { 4398 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4399 4400 if (!packet) 4401 goto nomem_pkt; 4402 4403 if (sctp_test_T_bit(abort)) 4404 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4405 4406 abort->skb->sk = ep->base.sk; 4407 4408 sctp_packet_append_chunk(packet, abort); 4409 4410 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4411 SCTP_PACKET(packet)); 4412 4413 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4414 } 4415 4416 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4417 4418 discard: 4419 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4420 return SCTP_DISPOSITION_ABORT; 4421 4422 nomem_pkt: 4423 sctp_chunk_free(abort); 4424 nomem: 4425 return SCTP_DISPOSITION_NOMEM; 4426 } 4427 4428 /* 4429 * Handle a protocol violation when the chunk length is invalid. 4430 * "Invalid" length is identified as smaller than the minimal length a 4431 * given chunk can be. For example, a SACK chunk has invalid length 4432 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4433 * 4434 * We inform the other end by sending an ABORT with a Protocol Violation 4435 * error code. 4436 * 4437 * Section: Not specified 4438 * Verification Tag: Nothing to do 4439 * Inputs 4440 * (endpoint, asoc, chunk) 4441 * 4442 * Outputs 4443 * (reply_msg, msg_up, counters) 4444 * 4445 * Generate an ABORT chunk and terminate the association. 4446 */ 4447 static sctp_disposition_t sctp_sf_violation_chunklen( 4448 struct net *net, 4449 const struct sctp_endpoint *ep, 4450 const struct sctp_association *asoc, 4451 const sctp_subtype_t type, 4452 void *arg, 4453 sctp_cmd_seq_t *commands) 4454 { 4455 static const char err_str[]="The following chunk had invalid length:"; 4456 4457 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4458 sizeof(err_str)); 4459 } 4460 4461 /* 4462 * Handle a protocol violation when the parameter length is invalid. 4463 * If the length is smaller than the minimum length of a given parameter, 4464 * or accumulated length in multi parameters exceeds the end of the chunk, 4465 * the length is considered as invalid. 4466 */ 4467 static sctp_disposition_t sctp_sf_violation_paramlen( 4468 struct net *net, 4469 const struct sctp_endpoint *ep, 4470 const struct sctp_association *asoc, 4471 const sctp_subtype_t type, 4472 void *arg, void *ext, 4473 sctp_cmd_seq_t *commands) 4474 { 4475 struct sctp_chunk *chunk = arg; 4476 struct sctp_paramhdr *param = ext; 4477 struct sctp_chunk *abort = NULL; 4478 4479 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4480 goto discard; 4481 4482 /* Make the abort chunk. */ 4483 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4484 if (!abort) 4485 goto nomem; 4486 4487 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4488 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4489 4490 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4491 SCTP_ERROR(ECONNABORTED)); 4492 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4493 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4494 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4495 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4496 4497 discard: 4498 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4499 return SCTP_DISPOSITION_ABORT; 4500 nomem: 4501 return SCTP_DISPOSITION_NOMEM; 4502 } 4503 4504 /* Handle a protocol violation when the peer trying to advance the 4505 * cumulative tsn ack to a point beyond the max tsn currently sent. 4506 * 4507 * We inform the other end by sending an ABORT with a Protocol Violation 4508 * error code. 4509 */ 4510 static sctp_disposition_t sctp_sf_violation_ctsn( 4511 struct net *net, 4512 const struct sctp_endpoint *ep, 4513 const struct sctp_association *asoc, 4514 const sctp_subtype_t type, 4515 void *arg, 4516 sctp_cmd_seq_t *commands) 4517 { 4518 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4519 4520 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4521 sizeof(err_str)); 4522 } 4523 4524 /* Handle protocol violation of an invalid chunk bundling. For example, 4525 * when we have an association and we receive bundled INIT-ACK, or 4526 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4527 * statement from the specs. Additionally, there might be an attacker 4528 * on the path and we may not want to continue this communication. 4529 */ 4530 static sctp_disposition_t sctp_sf_violation_chunk( 4531 struct net *net, 4532 const struct sctp_endpoint *ep, 4533 const struct sctp_association *asoc, 4534 const sctp_subtype_t type, 4535 void *arg, 4536 sctp_cmd_seq_t *commands) 4537 { 4538 static const char err_str[]="The following chunk violates protocol:"; 4539 4540 if (!asoc) 4541 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4542 4543 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4544 sizeof(err_str)); 4545 } 4546 /*************************************************************************** 4547 * These are the state functions for handling primitive (Section 10) events. 4548 ***************************************************************************/ 4549 /* 4550 * sctp_sf_do_prm_asoc 4551 * 4552 * Section: 10.1 ULP-to-SCTP 4553 * B) Associate 4554 * 4555 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4556 * outbound stream count) 4557 * -> association id [,destination transport addr list] [,outbound stream 4558 * count] 4559 * 4560 * This primitive allows the upper layer to initiate an association to a 4561 * specific peer endpoint. 4562 * 4563 * The peer endpoint shall be specified by one of the transport addresses 4564 * which defines the endpoint (see Section 1.4). If the local SCTP 4565 * instance has not been initialized, the ASSOCIATE is considered an 4566 * error. 4567 * [This is not relevant for the kernel implementation since we do all 4568 * initialization at boot time. It we hadn't initialized we wouldn't 4569 * get anywhere near this code.] 4570 * 4571 * An association id, which is a local handle to the SCTP association, 4572 * will be returned on successful establishment of the association. If 4573 * SCTP is not able to open an SCTP association with the peer endpoint, 4574 * an error is returned. 4575 * [In the kernel implementation, the struct sctp_association needs to 4576 * be created BEFORE causing this primitive to run.] 4577 * 4578 * Other association parameters may be returned, including the 4579 * complete destination transport addresses of the peer as well as the 4580 * outbound stream count of the local endpoint. One of the transport 4581 * address from the returned destination addresses will be selected by 4582 * the local endpoint as default primary path for sending SCTP packets 4583 * to this peer. The returned "destination transport addr list" can 4584 * be used by the ULP to change the default primary path or to force 4585 * sending a packet to a specific transport address. [All of this 4586 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4587 * function.] 4588 * 4589 * Mandatory attributes: 4590 * 4591 * o local SCTP instance name - obtained from the INITIALIZE operation. 4592 * [This is the argument asoc.] 4593 * o destination transport addr - specified as one of the transport 4594 * addresses of the peer endpoint with which the association is to be 4595 * established. 4596 * [This is asoc->peer.active_path.] 4597 * o outbound stream count - the number of outbound streams the ULP 4598 * would like to open towards this peer endpoint. 4599 * [BUG: This is not currently implemented.] 4600 * Optional attributes: 4601 * 4602 * None. 4603 * 4604 * The return value is a disposition. 4605 */ 4606 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4607 const struct sctp_endpoint *ep, 4608 const struct sctp_association *asoc, 4609 const sctp_subtype_t type, 4610 void *arg, 4611 sctp_cmd_seq_t *commands) 4612 { 4613 struct sctp_chunk *repl; 4614 struct sctp_association* my_asoc; 4615 4616 /* The comment below says that we enter COOKIE-WAIT AFTER 4617 * sending the INIT, but that doesn't actually work in our 4618 * implementation... 4619 */ 4620 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4621 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4622 4623 /* RFC 2960 5.1 Normal Establishment of an Association 4624 * 4625 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4626 * must provide its Verification Tag (Tag_A) in the Initiate 4627 * Tag field. Tag_A SHOULD be a random number in the range of 4628 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4629 */ 4630 4631 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4632 if (!repl) 4633 goto nomem; 4634 4635 /* Cast away the const modifier, as we want to just 4636 * rerun it through as a sideffect. 4637 */ 4638 my_asoc = (struct sctp_association *)asoc; 4639 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4640 4641 /* Choose transport for INIT. */ 4642 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4643 SCTP_CHUNK(repl)); 4644 4645 /* After sending the INIT, "A" starts the T1-init timer and 4646 * enters the COOKIE-WAIT state. 4647 */ 4648 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4649 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4650 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4651 return SCTP_DISPOSITION_CONSUME; 4652 4653 nomem: 4654 return SCTP_DISPOSITION_NOMEM; 4655 } 4656 4657 /* 4658 * Process the SEND primitive. 4659 * 4660 * Section: 10.1 ULP-to-SCTP 4661 * E) Send 4662 * 4663 * Format: SEND(association id, buffer address, byte count [,context] 4664 * [,stream id] [,life time] [,destination transport address] 4665 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4666 * -> result 4667 * 4668 * This is the main method to send user data via SCTP. 4669 * 4670 * Mandatory attributes: 4671 * 4672 * o association id - local handle to the SCTP association 4673 * 4674 * o buffer address - the location where the user message to be 4675 * transmitted is stored; 4676 * 4677 * o byte count - The size of the user data in number of bytes; 4678 * 4679 * Optional attributes: 4680 * 4681 * o context - an optional 32 bit integer that will be carried in the 4682 * sending failure notification to the ULP if the transportation of 4683 * this User Message fails. 4684 * 4685 * o stream id - to indicate which stream to send the data on. If not 4686 * specified, stream 0 will be used. 4687 * 4688 * o life time - specifies the life time of the user data. The user data 4689 * will not be sent by SCTP after the life time expires. This 4690 * parameter can be used to avoid efforts to transmit stale 4691 * user messages. SCTP notifies the ULP if the data cannot be 4692 * initiated to transport (i.e. sent to the destination via SCTP's 4693 * send primitive) within the life time variable. However, the 4694 * user data will be transmitted if SCTP has attempted to transmit a 4695 * chunk before the life time expired. 4696 * 4697 * o destination transport address - specified as one of the destination 4698 * transport addresses of the peer endpoint to which this packet 4699 * should be sent. Whenever possible, SCTP should use this destination 4700 * transport address for sending the packets, instead of the current 4701 * primary path. 4702 * 4703 * o unorder flag - this flag, if present, indicates that the user 4704 * would like the data delivered in an unordered fashion to the peer 4705 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4706 * message). 4707 * 4708 * o no-bundle flag - instructs SCTP not to bundle this user data with 4709 * other outbound DATA chunks. SCTP MAY still bundle even when 4710 * this flag is present, when faced with network congestion. 4711 * 4712 * o payload protocol-id - A 32 bit unsigned integer that is to be 4713 * passed to the peer indicating the type of payload protocol data 4714 * being transmitted. This value is passed as opaque data by SCTP. 4715 * 4716 * The return value is the disposition. 4717 */ 4718 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4719 const struct sctp_endpoint *ep, 4720 const struct sctp_association *asoc, 4721 const sctp_subtype_t type, 4722 void *arg, 4723 sctp_cmd_seq_t *commands) 4724 { 4725 struct sctp_datamsg *msg = arg; 4726 4727 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4728 return SCTP_DISPOSITION_CONSUME; 4729 } 4730 4731 /* 4732 * Process the SHUTDOWN primitive. 4733 * 4734 * Section: 10.1: 4735 * C) Shutdown 4736 * 4737 * Format: SHUTDOWN(association id) 4738 * -> result 4739 * 4740 * Gracefully closes an association. Any locally queued user data 4741 * will be delivered to the peer. The association will be terminated only 4742 * after the peer acknowledges all the SCTP packets sent. A success code 4743 * will be returned on successful termination of the association. If 4744 * attempting to terminate the association results in a failure, an error 4745 * code shall be returned. 4746 * 4747 * Mandatory attributes: 4748 * 4749 * o association id - local handle to the SCTP association 4750 * 4751 * Optional attributes: 4752 * 4753 * None. 4754 * 4755 * The return value is the disposition. 4756 */ 4757 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4758 struct net *net, 4759 const struct sctp_endpoint *ep, 4760 const struct sctp_association *asoc, 4761 const sctp_subtype_t type, 4762 void *arg, 4763 sctp_cmd_seq_t *commands) 4764 { 4765 int disposition; 4766 4767 /* From 9.2 Shutdown of an Association 4768 * Upon receipt of the SHUTDOWN primitive from its upper 4769 * layer, the endpoint enters SHUTDOWN-PENDING state and 4770 * remains there until all outstanding data has been 4771 * acknowledged by its peer. The endpoint accepts no new data 4772 * from its upper layer, but retransmits data to the far end 4773 * if necessary to fill gaps. 4774 */ 4775 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4776 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4777 4778 disposition = SCTP_DISPOSITION_CONSUME; 4779 if (sctp_outq_is_empty(&asoc->outqueue)) { 4780 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4781 arg, commands); 4782 } 4783 return disposition; 4784 } 4785 4786 /* 4787 * Process the ABORT primitive. 4788 * 4789 * Section: 10.1: 4790 * C) Abort 4791 * 4792 * Format: Abort(association id [, cause code]) 4793 * -> result 4794 * 4795 * Ungracefully closes an association. Any locally queued user data 4796 * will be discarded and an ABORT chunk is sent to the peer. A success code 4797 * will be returned on successful abortion of the association. If 4798 * attempting to abort the association results in a failure, an error 4799 * code shall be returned. 4800 * 4801 * Mandatory attributes: 4802 * 4803 * o association id - local handle to the SCTP association 4804 * 4805 * Optional attributes: 4806 * 4807 * o cause code - reason of the abort to be passed to the peer 4808 * 4809 * None. 4810 * 4811 * The return value is the disposition. 4812 */ 4813 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4814 struct net *net, 4815 const struct sctp_endpoint *ep, 4816 const struct sctp_association *asoc, 4817 const sctp_subtype_t type, 4818 void *arg, 4819 sctp_cmd_seq_t *commands) 4820 { 4821 /* From 9.1 Abort of an Association 4822 * Upon receipt of the ABORT primitive from its upper 4823 * layer, the endpoint enters CLOSED state and 4824 * discard all outstanding data has been 4825 * acknowledged by its peer. The endpoint accepts no new data 4826 * from its upper layer, but retransmits data to the far end 4827 * if necessary to fill gaps. 4828 */ 4829 struct sctp_chunk *abort = arg; 4830 sctp_disposition_t retval; 4831 4832 retval = SCTP_DISPOSITION_CONSUME; 4833 4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4835 4836 /* Even if we can't send the ABORT due to low memory delete the 4837 * TCB. This is a departure from our typical NOMEM handling. 4838 */ 4839 4840 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4841 SCTP_ERROR(ECONNABORTED)); 4842 /* Delete the established association. */ 4843 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4844 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4845 4846 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4847 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4848 4849 return retval; 4850 } 4851 4852 /* We tried an illegal operation on an association which is closed. */ 4853 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4854 const struct sctp_endpoint *ep, 4855 const struct sctp_association *asoc, 4856 const sctp_subtype_t type, 4857 void *arg, 4858 sctp_cmd_seq_t *commands) 4859 { 4860 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4861 return SCTP_DISPOSITION_CONSUME; 4862 } 4863 4864 /* We tried an illegal operation on an association which is shutting 4865 * down. 4866 */ 4867 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4868 const struct sctp_endpoint *ep, 4869 const struct sctp_association *asoc, 4870 const sctp_subtype_t type, 4871 void *arg, 4872 sctp_cmd_seq_t *commands) 4873 { 4874 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4875 SCTP_ERROR(-ESHUTDOWN)); 4876 return SCTP_DISPOSITION_CONSUME; 4877 } 4878 4879 /* 4880 * sctp_cookie_wait_prm_shutdown 4881 * 4882 * Section: 4 Note: 2 4883 * Verification Tag: 4884 * Inputs 4885 * (endpoint, asoc) 4886 * 4887 * The RFC does not explicitly address this issue, but is the route through the 4888 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4889 * 4890 * Outputs 4891 * (timers) 4892 */ 4893 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4894 struct net *net, 4895 const struct sctp_endpoint *ep, 4896 const struct sctp_association *asoc, 4897 const sctp_subtype_t type, 4898 void *arg, 4899 sctp_cmd_seq_t *commands) 4900 { 4901 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4902 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4903 4904 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4905 SCTP_STATE(SCTP_STATE_CLOSED)); 4906 4907 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4908 4909 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4910 4911 return SCTP_DISPOSITION_DELETE_TCB; 4912 } 4913 4914 /* 4915 * sctp_cookie_echoed_prm_shutdown 4916 * 4917 * Section: 4 Note: 2 4918 * Verification Tag: 4919 * Inputs 4920 * (endpoint, asoc) 4921 * 4922 * The RFC does not explcitly address this issue, but is the route through the 4923 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4924 * 4925 * Outputs 4926 * (timers) 4927 */ 4928 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4929 struct net *net, 4930 const struct sctp_endpoint *ep, 4931 const struct sctp_association *asoc, 4932 const sctp_subtype_t type, 4933 void *arg, sctp_cmd_seq_t *commands) 4934 { 4935 /* There is a single T1 timer, so we should be able to use 4936 * common function with the COOKIE-WAIT state. 4937 */ 4938 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4939 } 4940 4941 /* 4942 * sctp_sf_cookie_wait_prm_abort 4943 * 4944 * Section: 4 Note: 2 4945 * Verification Tag: 4946 * Inputs 4947 * (endpoint, asoc) 4948 * 4949 * The RFC does not explicitly address this issue, but is the route through the 4950 * state table when someone issues an abort while in COOKIE_WAIT state. 4951 * 4952 * Outputs 4953 * (timers) 4954 */ 4955 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4956 struct net *net, 4957 const struct sctp_endpoint *ep, 4958 const struct sctp_association *asoc, 4959 const sctp_subtype_t type, 4960 void *arg, 4961 sctp_cmd_seq_t *commands) 4962 { 4963 struct sctp_chunk *abort = arg; 4964 sctp_disposition_t retval; 4965 4966 /* Stop T1-init timer */ 4967 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4968 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4969 retval = SCTP_DISPOSITION_CONSUME; 4970 4971 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4972 4973 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4974 SCTP_STATE(SCTP_STATE_CLOSED)); 4975 4976 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4977 4978 /* Even if we can't send the ABORT due to low memory delete the 4979 * TCB. This is a departure from our typical NOMEM handling. 4980 */ 4981 4982 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4983 SCTP_ERROR(ECONNREFUSED)); 4984 /* Delete the established association. */ 4985 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4986 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4987 4988 return retval; 4989 } 4990 4991 /* 4992 * sctp_sf_cookie_echoed_prm_abort 4993 * 4994 * Section: 4 Note: 3 4995 * Verification Tag: 4996 * Inputs 4997 * (endpoint, asoc) 4998 * 4999 * The RFC does not explcitly address this issue, but is the route through the 5000 * state table when someone issues an abort while in COOKIE_ECHOED state. 5001 * 5002 * Outputs 5003 * (timers) 5004 */ 5005 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5006 struct net *net, 5007 const struct sctp_endpoint *ep, 5008 const struct sctp_association *asoc, 5009 const sctp_subtype_t type, 5010 void *arg, 5011 sctp_cmd_seq_t *commands) 5012 { 5013 /* There is a single T1 timer, so we should be able to use 5014 * common function with the COOKIE-WAIT state. 5015 */ 5016 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5017 } 5018 5019 /* 5020 * sctp_sf_shutdown_pending_prm_abort 5021 * 5022 * Inputs 5023 * (endpoint, asoc) 5024 * 5025 * The RFC does not explicitly address this issue, but is the route through the 5026 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5027 * 5028 * Outputs 5029 * (timers) 5030 */ 5031 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5032 struct net *net, 5033 const struct sctp_endpoint *ep, 5034 const struct sctp_association *asoc, 5035 const sctp_subtype_t type, 5036 void *arg, 5037 sctp_cmd_seq_t *commands) 5038 { 5039 /* Stop the T5-shutdown guard timer. */ 5040 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5041 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5042 5043 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5044 } 5045 5046 /* 5047 * sctp_sf_shutdown_sent_prm_abort 5048 * 5049 * Inputs 5050 * (endpoint, asoc) 5051 * 5052 * The RFC does not explicitly address this issue, but is the route through the 5053 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5054 * 5055 * Outputs 5056 * (timers) 5057 */ 5058 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5059 struct net *net, 5060 const struct sctp_endpoint *ep, 5061 const struct sctp_association *asoc, 5062 const sctp_subtype_t type, 5063 void *arg, 5064 sctp_cmd_seq_t *commands) 5065 { 5066 /* Stop the T2-shutdown timer. */ 5067 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5068 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5069 5070 /* Stop the T5-shutdown guard timer. */ 5071 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5072 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5073 5074 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5075 } 5076 5077 /* 5078 * sctp_sf_cookie_echoed_prm_abort 5079 * 5080 * Inputs 5081 * (endpoint, asoc) 5082 * 5083 * The RFC does not explcitly address this issue, but is the route through the 5084 * state table when someone issues an abort while in COOKIE_ECHOED state. 5085 * 5086 * Outputs 5087 * (timers) 5088 */ 5089 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5090 struct net *net, 5091 const struct sctp_endpoint *ep, 5092 const struct sctp_association *asoc, 5093 const sctp_subtype_t type, 5094 void *arg, 5095 sctp_cmd_seq_t *commands) 5096 { 5097 /* The same T2 timer, so we should be able to use 5098 * common function with the SHUTDOWN-SENT state. 5099 */ 5100 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5101 } 5102 5103 /* 5104 * Process the REQUESTHEARTBEAT primitive 5105 * 5106 * 10.1 ULP-to-SCTP 5107 * J) Request Heartbeat 5108 * 5109 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5110 * 5111 * -> result 5112 * 5113 * Instructs the local endpoint to perform a HeartBeat on the specified 5114 * destination transport address of the given association. The returned 5115 * result should indicate whether the transmission of the HEARTBEAT 5116 * chunk to the destination address is successful. 5117 * 5118 * Mandatory attributes: 5119 * 5120 * o association id - local handle to the SCTP association 5121 * 5122 * o destination transport address - the transport address of the 5123 * association on which a heartbeat should be issued. 5124 */ 5125 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5126 struct net *net, 5127 const struct sctp_endpoint *ep, 5128 const struct sctp_association *asoc, 5129 const sctp_subtype_t type, 5130 void *arg, 5131 sctp_cmd_seq_t *commands) 5132 { 5133 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5134 (struct sctp_transport *)arg, commands)) 5135 return SCTP_DISPOSITION_NOMEM; 5136 5137 /* 5138 * RFC 2960 (bis), section 8.3 5139 * 5140 * D) Request an on-demand HEARTBEAT on a specific destination 5141 * transport address of a given association. 5142 * 5143 * The endpoint should increment the respective error counter of 5144 * the destination transport address each time a HEARTBEAT is sent 5145 * to that address and not acknowledged within one RTO. 5146 * 5147 */ 5148 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5149 SCTP_TRANSPORT(arg)); 5150 return SCTP_DISPOSITION_CONSUME; 5151 } 5152 5153 /* 5154 * ADDIP Section 4.1 ASCONF Chunk Procedures 5155 * When an endpoint has an ASCONF signaled change to be sent to the 5156 * remote endpoint it should do A1 to A9 5157 */ 5158 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5159 const struct sctp_endpoint *ep, 5160 const struct sctp_association *asoc, 5161 const sctp_subtype_t type, 5162 void *arg, 5163 sctp_cmd_seq_t *commands) 5164 { 5165 struct sctp_chunk *chunk = arg; 5166 5167 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5168 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5169 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5170 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5171 return SCTP_DISPOSITION_CONSUME; 5172 } 5173 5174 /* 5175 * Ignore the primitive event 5176 * 5177 * The return value is the disposition of the primitive. 5178 */ 5179 sctp_disposition_t sctp_sf_ignore_primitive( 5180 struct net *net, 5181 const struct sctp_endpoint *ep, 5182 const struct sctp_association *asoc, 5183 const sctp_subtype_t type, 5184 void *arg, 5185 sctp_cmd_seq_t *commands) 5186 { 5187 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 5188 return SCTP_DISPOSITION_DISCARD; 5189 } 5190 5191 /*************************************************************************** 5192 * These are the state functions for the OTHER events. 5193 ***************************************************************************/ 5194 5195 /* 5196 * When the SCTP stack has no more user data to send or retransmit, this 5197 * notification is given to the user. Also, at the time when a user app 5198 * subscribes to this event, if there is no data to be sent or 5199 * retransmit, the stack will immediately send up this notification. 5200 */ 5201 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5202 struct net *net, 5203 const struct sctp_endpoint *ep, 5204 const struct sctp_association *asoc, 5205 const sctp_subtype_t type, 5206 void *arg, 5207 sctp_cmd_seq_t *commands) 5208 { 5209 struct sctp_ulpevent *event; 5210 5211 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5212 if (!event) 5213 return SCTP_DISPOSITION_NOMEM; 5214 5215 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5216 5217 return SCTP_DISPOSITION_CONSUME; 5218 } 5219 5220 /* 5221 * Start the shutdown negotiation. 5222 * 5223 * From Section 9.2: 5224 * Once all its outstanding data has been acknowledged, the endpoint 5225 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5226 * TSN Ack field the last sequential TSN it has received from the peer. 5227 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5228 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5229 * with the updated last sequential TSN received from its peer. 5230 * 5231 * The return value is the disposition. 5232 */ 5233 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5234 struct net *net, 5235 const struct sctp_endpoint *ep, 5236 const struct sctp_association *asoc, 5237 const sctp_subtype_t type, 5238 void *arg, 5239 sctp_cmd_seq_t *commands) 5240 { 5241 struct sctp_chunk *reply; 5242 5243 /* Once all its outstanding data has been acknowledged, the 5244 * endpoint shall send a SHUTDOWN chunk to its peer including 5245 * in the Cumulative TSN Ack field the last sequential TSN it 5246 * has received from the peer. 5247 */ 5248 reply = sctp_make_shutdown(asoc, NULL); 5249 if (!reply) 5250 goto nomem; 5251 5252 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5253 * T2-shutdown timer. 5254 */ 5255 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5256 5257 /* It shall then start the T2-shutdown timer */ 5258 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5259 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5260 5261 /* RFC 4960 Section 9.2 5262 * The sender of the SHUTDOWN MAY also start an overall guard timer 5263 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5264 */ 5265 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5266 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5267 5268 if (asoc->autoclose) 5269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5270 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5271 5272 /* and enter the SHUTDOWN-SENT state. */ 5273 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5274 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5275 5276 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5277 * 5278 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5279 * or SHUTDOWN-ACK. 5280 */ 5281 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5282 5283 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5284 5285 return SCTP_DISPOSITION_CONSUME; 5286 5287 nomem: 5288 return SCTP_DISPOSITION_NOMEM; 5289 } 5290 5291 /* 5292 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5293 * 5294 * From Section 9.2: 5295 * 5296 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5297 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5298 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5299 * endpoint must re-send the SHUTDOWN ACK. 5300 * 5301 * The return value is the disposition. 5302 */ 5303 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5304 struct net *net, 5305 const struct sctp_endpoint *ep, 5306 const struct sctp_association *asoc, 5307 const sctp_subtype_t type, 5308 void *arg, 5309 sctp_cmd_seq_t *commands) 5310 { 5311 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5312 struct sctp_chunk *reply; 5313 5314 /* There are 2 ways of getting here: 5315 * 1) called in response to a SHUTDOWN chunk 5316 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5317 * 5318 * For the case (2), the arg parameter is set to NULL. We need 5319 * to check that we have a chunk before accessing it's fields. 5320 */ 5321 if (chunk) { 5322 if (!sctp_vtag_verify(chunk, asoc)) 5323 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5324 5325 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5326 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5327 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5328 commands); 5329 } 5330 5331 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5332 * shall send a SHUTDOWN ACK ... 5333 */ 5334 reply = sctp_make_shutdown_ack(asoc, chunk); 5335 if (!reply) 5336 goto nomem; 5337 5338 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5339 * the T2-shutdown timer. 5340 */ 5341 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5342 5343 /* and start/restart a T2-shutdown timer of its own, */ 5344 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5345 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5346 5347 if (asoc->autoclose) 5348 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5349 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5350 5351 /* Enter the SHUTDOWN-ACK-SENT state. */ 5352 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5353 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5354 5355 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5356 * 5357 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5358 * or SHUTDOWN-ACK. 5359 */ 5360 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5361 5362 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5363 5364 return SCTP_DISPOSITION_CONSUME; 5365 5366 nomem: 5367 return SCTP_DISPOSITION_NOMEM; 5368 } 5369 5370 /* 5371 * Ignore the event defined as other 5372 * 5373 * The return value is the disposition of the event. 5374 */ 5375 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5376 const struct sctp_endpoint *ep, 5377 const struct sctp_association *asoc, 5378 const sctp_subtype_t type, 5379 void *arg, 5380 sctp_cmd_seq_t *commands) 5381 { 5382 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5383 return SCTP_DISPOSITION_DISCARD; 5384 } 5385 5386 /************************************************************ 5387 * These are the state functions for handling timeout events. 5388 ************************************************************/ 5389 5390 /* 5391 * RTX Timeout 5392 * 5393 * Section: 6.3.3 Handle T3-rtx Expiration 5394 * 5395 * Whenever the retransmission timer T3-rtx expires for a destination 5396 * address, do the following: 5397 * [See below] 5398 * 5399 * The return value is the disposition of the chunk. 5400 */ 5401 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5402 const struct sctp_endpoint *ep, 5403 const struct sctp_association *asoc, 5404 const sctp_subtype_t type, 5405 void *arg, 5406 sctp_cmd_seq_t *commands) 5407 { 5408 struct sctp_transport *transport = arg; 5409 5410 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5411 5412 if (asoc->overall_error_count >= asoc->max_retrans) { 5413 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5414 /* 5415 * We are here likely because the receiver had its rwnd 5416 * closed for a while and we have not been able to 5417 * transmit the locally queued data within the maximum 5418 * retransmission attempts limit. Start the T5 5419 * shutdown guard timer to give the receiver one last 5420 * chance and some additional time to recover before 5421 * aborting. 5422 */ 5423 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5424 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5425 } else { 5426 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5427 SCTP_ERROR(ETIMEDOUT)); 5428 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5429 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5430 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5431 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5432 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5433 return SCTP_DISPOSITION_DELETE_TCB; 5434 } 5435 } 5436 5437 /* E1) For the destination address for which the timer 5438 * expires, adjust its ssthresh with rules defined in Section 5439 * 7.2.3 and set the cwnd <- MTU. 5440 */ 5441 5442 /* E2) For the destination address for which the timer 5443 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5444 * maximum value discussed in rule C7 above (RTO.max) may be 5445 * used to provide an upper bound to this doubling operation. 5446 */ 5447 5448 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5449 * outstanding DATA chunks for the address for which the 5450 * T3-rtx has expired will fit into a single packet, subject 5451 * to the MTU constraint for the path corresponding to the 5452 * destination transport address to which the retransmission 5453 * is being sent (this may be different from the address for 5454 * which the timer expires [see Section 6.4]). Call this 5455 * value K. Bundle and retransmit those K DATA chunks in a 5456 * single packet to the destination endpoint. 5457 * 5458 * Note: Any DATA chunks that were sent to the address for 5459 * which the T3-rtx timer expired but did not fit in one MTU 5460 * (rule E3 above), should be marked for retransmission and 5461 * sent as soon as cwnd allows (normally when a SACK arrives). 5462 */ 5463 5464 /* Do some failure management (Section 8.2). */ 5465 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5466 5467 /* NB: Rules E4 and F1 are implicit in R1. */ 5468 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5469 5470 return SCTP_DISPOSITION_CONSUME; 5471 } 5472 5473 /* 5474 * Generate delayed SACK on timeout 5475 * 5476 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5477 * 5478 * The guidelines on delayed acknowledgement algorithm specified in 5479 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5480 * acknowledgement SHOULD be generated for at least every second packet 5481 * (not every second DATA chunk) received, and SHOULD be generated 5482 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5483 * some situations it may be beneficial for an SCTP transmitter to be 5484 * more conservative than the algorithms detailed in this document 5485 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5486 * the following algorithms allow. 5487 */ 5488 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5489 const struct sctp_endpoint *ep, 5490 const struct sctp_association *asoc, 5491 const sctp_subtype_t type, 5492 void *arg, 5493 sctp_cmd_seq_t *commands) 5494 { 5495 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5496 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5497 return SCTP_DISPOSITION_CONSUME; 5498 } 5499 5500 /* 5501 * sctp_sf_t1_init_timer_expire 5502 * 5503 * Section: 4 Note: 2 5504 * Verification Tag: 5505 * Inputs 5506 * (endpoint, asoc) 5507 * 5508 * RFC 2960 Section 4 Notes 5509 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5510 * and re-start the T1-init timer without changing state. This MUST 5511 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5512 * endpoint MUST abort the initialization process and report the 5513 * error to SCTP user. 5514 * 5515 * Outputs 5516 * (timers, events) 5517 * 5518 */ 5519 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5520 const struct sctp_endpoint *ep, 5521 const struct sctp_association *asoc, 5522 const sctp_subtype_t type, 5523 void *arg, 5524 sctp_cmd_seq_t *commands) 5525 { 5526 struct sctp_chunk *repl = NULL; 5527 struct sctp_bind_addr *bp; 5528 int attempts = asoc->init_err_counter + 1; 5529 5530 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5531 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5532 5533 if (attempts <= asoc->max_init_attempts) { 5534 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5535 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5536 if (!repl) 5537 return SCTP_DISPOSITION_NOMEM; 5538 5539 /* Choose transport for INIT. */ 5540 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5541 SCTP_CHUNK(repl)); 5542 5543 /* Issue a sideeffect to do the needed accounting. */ 5544 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5545 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5546 5547 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5548 } else { 5549 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5550 " max_init_attempts: %d\n", 5551 attempts, asoc->max_init_attempts); 5552 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5553 SCTP_ERROR(ETIMEDOUT)); 5554 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5555 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5556 return SCTP_DISPOSITION_DELETE_TCB; 5557 } 5558 5559 return SCTP_DISPOSITION_CONSUME; 5560 } 5561 5562 /* 5563 * sctp_sf_t1_cookie_timer_expire 5564 * 5565 * Section: 4 Note: 2 5566 * Verification Tag: 5567 * Inputs 5568 * (endpoint, asoc) 5569 * 5570 * RFC 2960 Section 4 Notes 5571 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5572 * COOKIE ECHO and re-start the T1-cookie timer without changing 5573 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5574 * After that, the endpoint MUST abort the initialization process and 5575 * report the error to SCTP user. 5576 * 5577 * Outputs 5578 * (timers, events) 5579 * 5580 */ 5581 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5582 const struct sctp_endpoint *ep, 5583 const struct sctp_association *asoc, 5584 const sctp_subtype_t type, 5585 void *arg, 5586 sctp_cmd_seq_t *commands) 5587 { 5588 struct sctp_chunk *repl = NULL; 5589 int attempts = asoc->init_err_counter + 1; 5590 5591 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5592 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5593 5594 if (attempts <= asoc->max_init_attempts) { 5595 repl = sctp_make_cookie_echo(asoc, NULL); 5596 if (!repl) 5597 return SCTP_DISPOSITION_NOMEM; 5598 5599 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5600 SCTP_CHUNK(repl)); 5601 /* Issue a sideeffect to do the needed accounting. */ 5602 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5603 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5604 5605 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5606 } else { 5607 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5608 SCTP_ERROR(ETIMEDOUT)); 5609 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5610 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5611 return SCTP_DISPOSITION_DELETE_TCB; 5612 } 5613 5614 return SCTP_DISPOSITION_CONSUME; 5615 } 5616 5617 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5618 * with the updated last sequential TSN received from its peer. 5619 * 5620 * An endpoint should limit the number of retransmissions of the 5621 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5622 * If this threshold is exceeded the endpoint should destroy the TCB and 5623 * MUST report the peer endpoint unreachable to the upper layer (and 5624 * thus the association enters the CLOSED state). The reception of any 5625 * packet from its peer (i.e. as the peer sends all of its queued DATA 5626 * chunks) should clear the endpoint's retransmission count and restart 5627 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5628 * all of its queued DATA chunks that have not yet been sent. 5629 */ 5630 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5631 const struct sctp_endpoint *ep, 5632 const struct sctp_association *asoc, 5633 const sctp_subtype_t type, 5634 void *arg, 5635 sctp_cmd_seq_t *commands) 5636 { 5637 struct sctp_chunk *reply = NULL; 5638 5639 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5640 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5641 5642 ((struct sctp_association *)asoc)->shutdown_retries++; 5643 5644 if (asoc->overall_error_count >= asoc->max_retrans) { 5645 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5646 SCTP_ERROR(ETIMEDOUT)); 5647 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5648 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5649 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5650 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5651 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5652 return SCTP_DISPOSITION_DELETE_TCB; 5653 } 5654 5655 switch (asoc->state) { 5656 case SCTP_STATE_SHUTDOWN_SENT: 5657 reply = sctp_make_shutdown(asoc, NULL); 5658 break; 5659 5660 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5661 reply = sctp_make_shutdown_ack(asoc, NULL); 5662 break; 5663 5664 default: 5665 BUG(); 5666 break; 5667 } 5668 5669 if (!reply) 5670 goto nomem; 5671 5672 /* Do some failure management (Section 8.2). 5673 * If we remove the transport an SHUTDOWN was last sent to, don't 5674 * do failure management. 5675 */ 5676 if (asoc->shutdown_last_sent_to) 5677 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5678 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5679 5680 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5681 * the T2-shutdown timer. 5682 */ 5683 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5684 5685 /* Restart the T2-shutdown timer. */ 5686 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5687 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5688 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5689 return SCTP_DISPOSITION_CONSUME; 5690 5691 nomem: 5692 return SCTP_DISPOSITION_NOMEM; 5693 } 5694 5695 /* 5696 * ADDIP Section 4.1 ASCONF CHunk Procedures 5697 * If the T4 RTO timer expires the endpoint should do B1 to B5 5698 */ 5699 sctp_disposition_t sctp_sf_t4_timer_expire( 5700 struct net *net, 5701 const struct sctp_endpoint *ep, 5702 const struct sctp_association *asoc, 5703 const sctp_subtype_t type, 5704 void *arg, 5705 sctp_cmd_seq_t *commands) 5706 { 5707 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5708 struct sctp_transport *transport = chunk->transport; 5709 5710 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5711 5712 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5713 * detection on the appropriate destination address as defined in 5714 * RFC2960 [5] section 8.1 and 8.2. 5715 */ 5716 if (transport) 5717 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5718 SCTP_TRANSPORT(transport)); 5719 5720 /* Reconfig T4 timer and transport. */ 5721 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5722 5723 /* ADDIP 4.1 B2) Increment the association error counters and perform 5724 * endpoint failure detection on the association as defined in 5725 * RFC2960 [5] section 8.1 and 8.2. 5726 * association error counter is incremented in SCTP_CMD_STRIKE. 5727 */ 5728 if (asoc->overall_error_count >= asoc->max_retrans) { 5729 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5730 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5731 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5732 SCTP_ERROR(ETIMEDOUT)); 5733 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5734 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5735 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5736 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5737 return SCTP_DISPOSITION_ABORT; 5738 } 5739 5740 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5741 * the ASCONF chunk was sent by doubling the RTO timer value. 5742 * This is done in SCTP_CMD_STRIKE. 5743 */ 5744 5745 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5746 * choose an alternate destination address (please refer to RFC2960 5747 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5748 * chunk, it MUST be the same (including its serial number) as the last 5749 * ASCONF sent. 5750 */ 5751 sctp_chunk_hold(asoc->addip_last_asconf); 5752 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5753 SCTP_CHUNK(asoc->addip_last_asconf)); 5754 5755 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5756 * destination is selected, then the RTO used will be that of the new 5757 * destination address. 5758 */ 5759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5760 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5761 5762 return SCTP_DISPOSITION_CONSUME; 5763 } 5764 5765 /* sctpimpguide-05 Section 2.12.2 5766 * The sender of the SHUTDOWN MAY also start an overall guard timer 5767 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5768 * At the expiration of this timer the sender SHOULD abort the association 5769 * by sending an ABORT chunk. 5770 */ 5771 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5772 const struct sctp_endpoint *ep, 5773 const struct sctp_association *asoc, 5774 const sctp_subtype_t type, 5775 void *arg, 5776 sctp_cmd_seq_t *commands) 5777 { 5778 struct sctp_chunk *reply = NULL; 5779 5780 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5781 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5782 5783 reply = sctp_make_abort(asoc, NULL, 0); 5784 if (!reply) 5785 goto nomem; 5786 5787 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5788 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5789 SCTP_ERROR(ETIMEDOUT)); 5790 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5791 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5792 5793 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5794 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5795 5796 return SCTP_DISPOSITION_DELETE_TCB; 5797 nomem: 5798 return SCTP_DISPOSITION_NOMEM; 5799 } 5800 5801 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5802 * the association is automatically closed by starting the shutdown process. 5803 * The work that needs to be done is same as when SHUTDOWN is initiated by 5804 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5805 */ 5806 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5807 struct net *net, 5808 const struct sctp_endpoint *ep, 5809 const struct sctp_association *asoc, 5810 const sctp_subtype_t type, 5811 void *arg, 5812 sctp_cmd_seq_t *commands) 5813 { 5814 int disposition; 5815 5816 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5817 5818 /* From 9.2 Shutdown of an Association 5819 * Upon receipt of the SHUTDOWN primitive from its upper 5820 * layer, the endpoint enters SHUTDOWN-PENDING state and 5821 * remains there until all outstanding data has been 5822 * acknowledged by its peer. The endpoint accepts no new data 5823 * from its upper layer, but retransmits data to the far end 5824 * if necessary to fill gaps. 5825 */ 5826 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5827 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5828 5829 disposition = SCTP_DISPOSITION_CONSUME; 5830 if (sctp_outq_is_empty(&asoc->outqueue)) { 5831 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5832 arg, commands); 5833 } 5834 return disposition; 5835 } 5836 5837 /***************************************************************************** 5838 * These are sa state functions which could apply to all types of events. 5839 ****************************************************************************/ 5840 5841 /* 5842 * This table entry is not implemented. 5843 * 5844 * Inputs 5845 * (endpoint, asoc, chunk) 5846 * 5847 * The return value is the disposition of the chunk. 5848 */ 5849 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5850 const struct sctp_endpoint *ep, 5851 const struct sctp_association *asoc, 5852 const sctp_subtype_t type, 5853 void *arg, 5854 sctp_cmd_seq_t *commands) 5855 { 5856 return SCTP_DISPOSITION_NOT_IMPL; 5857 } 5858 5859 /* 5860 * This table entry represents a bug. 5861 * 5862 * Inputs 5863 * (endpoint, asoc, chunk) 5864 * 5865 * The return value is the disposition of the chunk. 5866 */ 5867 sctp_disposition_t sctp_sf_bug(struct net *net, 5868 const struct sctp_endpoint *ep, 5869 const struct sctp_association *asoc, 5870 const sctp_subtype_t type, 5871 void *arg, 5872 sctp_cmd_seq_t *commands) 5873 { 5874 return SCTP_DISPOSITION_BUG; 5875 } 5876 5877 /* 5878 * This table entry represents the firing of a timer in the wrong state. 5879 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5880 * when the association is in the wrong state. This event should 5881 * be ignored, so as to prevent any rearming of the timer. 5882 * 5883 * Inputs 5884 * (endpoint, asoc, chunk) 5885 * 5886 * The return value is the disposition of the chunk. 5887 */ 5888 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5889 const struct sctp_endpoint *ep, 5890 const struct sctp_association *asoc, 5891 const sctp_subtype_t type, 5892 void *arg, 5893 sctp_cmd_seq_t *commands) 5894 { 5895 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5896 return SCTP_DISPOSITION_CONSUME; 5897 } 5898 5899 /******************************************************************** 5900 * 2nd Level Abstractions 5901 ********************************************************************/ 5902 5903 /* Pull the SACK chunk based on the SACK header. */ 5904 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5905 { 5906 struct sctp_sackhdr *sack; 5907 unsigned int len; 5908 __u16 num_blocks; 5909 __u16 num_dup_tsns; 5910 5911 /* Protect ourselves from reading too far into 5912 * the skb from a bogus sender. 5913 */ 5914 sack = (struct sctp_sackhdr *) chunk->skb->data; 5915 5916 num_blocks = ntohs(sack->num_gap_ack_blocks); 5917 num_dup_tsns = ntohs(sack->num_dup_tsns); 5918 len = sizeof(struct sctp_sackhdr); 5919 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5920 if (len > chunk->skb->len) 5921 return NULL; 5922 5923 skb_pull(chunk->skb, len); 5924 5925 return sack; 5926 } 5927 5928 /* Create an ABORT packet to be sent as a response, with the specified 5929 * error causes. 5930 */ 5931 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5932 const struct sctp_endpoint *ep, 5933 const struct sctp_association *asoc, 5934 struct sctp_chunk *chunk, 5935 const void *payload, 5936 size_t paylen) 5937 { 5938 struct sctp_packet *packet; 5939 struct sctp_chunk *abort; 5940 5941 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5942 5943 if (packet) { 5944 /* Make an ABORT. 5945 * The T bit will be set if the asoc is NULL. 5946 */ 5947 abort = sctp_make_abort(asoc, chunk, paylen); 5948 if (!abort) { 5949 sctp_ootb_pkt_free(packet); 5950 return NULL; 5951 } 5952 5953 /* Reflect vtag if T-Bit is set */ 5954 if (sctp_test_T_bit(abort)) 5955 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5956 5957 /* Add specified error causes, i.e., payload, to the 5958 * end of the chunk. 5959 */ 5960 sctp_addto_chunk(abort, paylen, payload); 5961 5962 /* Set the skb to the belonging sock for accounting. */ 5963 abort->skb->sk = ep->base.sk; 5964 5965 sctp_packet_append_chunk(packet, abort); 5966 5967 } 5968 5969 return packet; 5970 } 5971 5972 /* Allocate a packet for responding in the OOTB conditions. */ 5973 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5974 const struct sctp_association *asoc, 5975 const struct sctp_chunk *chunk) 5976 { 5977 struct sctp_packet *packet; 5978 struct sctp_transport *transport; 5979 __u16 sport; 5980 __u16 dport; 5981 __u32 vtag; 5982 5983 /* Get the source and destination port from the inbound packet. */ 5984 sport = ntohs(chunk->sctp_hdr->dest); 5985 dport = ntohs(chunk->sctp_hdr->source); 5986 5987 /* The V-tag is going to be the same as the inbound packet if no 5988 * association exists, otherwise, use the peer's vtag. 5989 */ 5990 if (asoc) { 5991 /* Special case the INIT-ACK as there is no peer's vtag 5992 * yet. 5993 */ 5994 switch(chunk->chunk_hdr->type) { 5995 case SCTP_CID_INIT_ACK: 5996 { 5997 sctp_initack_chunk_t *initack; 5998 5999 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6000 vtag = ntohl(initack->init_hdr.init_tag); 6001 break; 6002 } 6003 default: 6004 vtag = asoc->peer.i.init_tag; 6005 break; 6006 } 6007 } else { 6008 /* Special case the INIT and stale COOKIE_ECHO as there is no 6009 * vtag yet. 6010 */ 6011 switch(chunk->chunk_hdr->type) { 6012 case SCTP_CID_INIT: 6013 { 6014 sctp_init_chunk_t *init; 6015 6016 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6017 vtag = ntohl(init->init_hdr.init_tag); 6018 break; 6019 } 6020 default: 6021 vtag = ntohl(chunk->sctp_hdr->vtag); 6022 break; 6023 } 6024 } 6025 6026 /* Make a transport for the bucket, Eliza... */ 6027 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6028 if (!transport) 6029 goto nomem; 6030 6031 /* Cache a route for the transport with the chunk's destination as 6032 * the source address. 6033 */ 6034 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6035 sctp_sk(net->sctp.ctl_sock)); 6036 6037 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6038 packet = sctp_packet_config(packet, vtag, 0); 6039 6040 return packet; 6041 6042 nomem: 6043 return NULL; 6044 } 6045 6046 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6047 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6048 { 6049 sctp_transport_free(packet->transport); 6050 } 6051 6052 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6053 static void sctp_send_stale_cookie_err(struct net *net, 6054 const struct sctp_endpoint *ep, 6055 const struct sctp_association *asoc, 6056 const struct sctp_chunk *chunk, 6057 sctp_cmd_seq_t *commands, 6058 struct sctp_chunk *err_chunk) 6059 { 6060 struct sctp_packet *packet; 6061 6062 if (err_chunk) { 6063 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6064 if (packet) { 6065 struct sctp_signed_cookie *cookie; 6066 6067 /* Override the OOTB vtag from the cookie. */ 6068 cookie = chunk->subh.cookie_hdr; 6069 packet->vtag = cookie->c.peer_vtag; 6070 6071 /* Set the skb to the belonging sock for accounting. */ 6072 err_chunk->skb->sk = ep->base.sk; 6073 sctp_packet_append_chunk(packet, err_chunk); 6074 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6075 SCTP_PACKET(packet)); 6076 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6077 } else 6078 sctp_chunk_free (err_chunk); 6079 } 6080 } 6081 6082 6083 /* Process a data chunk */ 6084 static int sctp_eat_data(const struct sctp_association *asoc, 6085 struct sctp_chunk *chunk, 6086 sctp_cmd_seq_t *commands) 6087 { 6088 sctp_datahdr_t *data_hdr; 6089 struct sctp_chunk *err; 6090 size_t datalen; 6091 sctp_verb_t deliver; 6092 int tmp; 6093 __u32 tsn; 6094 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6095 struct sock *sk = asoc->base.sk; 6096 struct net *net = sock_net(sk); 6097 u16 ssn; 6098 u16 sid; 6099 u8 ordered = 0; 6100 6101 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6102 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6103 6104 tsn = ntohl(data_hdr->tsn); 6105 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 6106 6107 /* ASSERT: Now skb->data is really the user data. */ 6108 6109 /* Process ECN based congestion. 6110 * 6111 * Since the chunk structure is reused for all chunks within 6112 * a packet, we use ecn_ce_done to track if we've already 6113 * done CE processing for this packet. 6114 * 6115 * We need to do ECN processing even if we plan to discard the 6116 * chunk later. 6117 */ 6118 6119 if (!chunk->ecn_ce_done) { 6120 struct sctp_af *af; 6121 chunk->ecn_ce_done = 1; 6122 6123 af = sctp_get_af_specific( 6124 ipver2af(ip_hdr(chunk->skb)->version)); 6125 6126 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6127 /* Do real work as sideffect. */ 6128 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6129 SCTP_U32(tsn)); 6130 } 6131 } 6132 6133 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6134 if (tmp < 0) { 6135 /* The TSN is too high--silently discard the chunk and 6136 * count on it getting retransmitted later. 6137 */ 6138 if (chunk->asoc) 6139 chunk->asoc->stats.outofseqtsns++; 6140 return SCTP_IERROR_HIGH_TSN; 6141 } else if (tmp > 0) { 6142 /* This is a duplicate. Record it. */ 6143 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6144 return SCTP_IERROR_DUP_TSN; 6145 } 6146 6147 /* This is a new TSN. */ 6148 6149 /* Discard if there is no room in the receive window. 6150 * Actually, allow a little bit of overflow (up to a MTU). 6151 */ 6152 datalen = ntohs(chunk->chunk_hdr->length); 6153 datalen -= sizeof(sctp_data_chunk_t); 6154 6155 deliver = SCTP_CMD_CHUNK_ULP; 6156 6157 /* Think about partial delivery. */ 6158 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6159 6160 /* Even if we don't accept this chunk there is 6161 * memory pressure. 6162 */ 6163 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6164 } 6165 6166 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6167 * seems a bit troublesome in that frag_point varies based on 6168 * PMTU. In cases, such as loopback, this might be a rather 6169 * large spill over. 6170 */ 6171 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6172 (datalen > asoc->rwnd + asoc->frag_point))) { 6173 6174 /* If this is the next TSN, consider reneging to make 6175 * room. Note: Playing nice with a confused sender. A 6176 * malicious sender can still eat up all our buffer 6177 * space and in the future we may want to detect and 6178 * do more drastic reneging. 6179 */ 6180 if (sctp_tsnmap_has_gap(map) && 6181 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6182 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 6183 deliver = SCTP_CMD_RENEGE; 6184 } else { 6185 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 6186 "rwnd: %d\n", tsn, datalen, 6187 asoc->rwnd); 6188 return SCTP_IERROR_IGNORE_TSN; 6189 } 6190 } 6191 6192 /* 6193 * Also try to renege to limit our memory usage in the event that 6194 * we are under memory pressure 6195 * If we can't renege, don't worry about it, the sk_rmem_schedule 6196 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6197 * memory usage too much 6198 */ 6199 if (*sk->sk_prot_creator->memory_pressure) { 6200 if (sctp_tsnmap_has_gap(map) && 6201 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6202 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 6203 deliver = SCTP_CMD_RENEGE; 6204 } 6205 } 6206 6207 /* 6208 * Section 3.3.10.9 No User Data (9) 6209 * 6210 * Cause of error 6211 * --------------- 6212 * No User Data: This error cause is returned to the originator of a 6213 * DATA chunk if a received DATA chunk has no user data. 6214 */ 6215 if (unlikely(0 == datalen)) { 6216 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6217 if (err) { 6218 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6219 SCTP_CHUNK(err)); 6220 } 6221 /* We are going to ABORT, so we might as well stop 6222 * processing the rest of the chunks in the packet. 6223 */ 6224 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6225 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6226 SCTP_ERROR(ECONNABORTED)); 6227 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6228 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6229 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6230 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6231 return SCTP_IERROR_NO_DATA; 6232 } 6233 6234 chunk->data_accepted = 1; 6235 6236 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6237 * if we renege and the chunk arrives again. 6238 */ 6239 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6240 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6241 if (chunk->asoc) 6242 chunk->asoc->stats.iuodchunks++; 6243 } else { 6244 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6245 if (chunk->asoc) 6246 chunk->asoc->stats.iodchunks++; 6247 ordered = 1; 6248 } 6249 6250 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6251 * 6252 * If an endpoint receive a DATA chunk with an invalid stream 6253 * identifier, it shall acknowledge the reception of the DATA chunk 6254 * following the normal procedure, immediately send an ERROR chunk 6255 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6256 * and discard the DATA chunk. 6257 */ 6258 sid = ntohs(data_hdr->stream); 6259 if (sid >= asoc->c.sinit_max_instreams) { 6260 /* Mark tsn as received even though we drop it */ 6261 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6262 6263 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6264 &data_hdr->stream, 6265 sizeof(data_hdr->stream), 6266 sizeof(u16)); 6267 if (err) 6268 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6269 SCTP_CHUNK(err)); 6270 return SCTP_IERROR_BAD_STREAM; 6271 } 6272 6273 /* Check to see if the SSN is possible for this TSN. 6274 * The biggest gap we can record is 4K wide. Since SSNs wrap 6275 * at an unsigned short, there is no way that an SSN can 6276 * wrap and for a valid TSN. We can simply check if the current 6277 * SSN is smaller then the next expected one. If it is, it wrapped 6278 * and is invalid. 6279 */ 6280 ssn = ntohs(data_hdr->ssn); 6281 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6282 return SCTP_IERROR_PROTO_VIOLATION; 6283 } 6284 6285 /* Send the data up to the user. Note: Schedule the 6286 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6287 * chunk needs the updated rwnd. 6288 */ 6289 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6290 6291 return SCTP_IERROR_NO_ERROR; 6292 } 6293